[llvm] [UniformityAnalysis] Replace DenseMap with SmallVector indexed by block number. NFC (PR #210564)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `llvm-clang-x86_64-sie-ubuntu-fast` running on `sie-linux-worker` while building `llvm` at step 6 "test-build-unified-tree-check-all".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/144/builds/59595

<details>
<summary>Here is the relevant piece of the build log for the reference</summary>

```
Step 6 (test-build-unified-tree-check-all) failure: test (failure)
******************** TEST 'Clang :: ClangScanDeps/logging-two-threads.c' FAILED ********************
Exit Code: 1

Command Output (stdout):
--
# RUN: at line 5
rm -rf /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/build/tools/clang/test/ClangScanDeps/Output/logging-two-threads.c.tmp
# executed command: rm -rf /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/build/tools/clang/test/ClangScanDeps/Output/logging-two-threads.c.tmp
# note: command had no output on stdout or stderr
# RUN: at line 6
split-file /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/llvm-project/clang/test/ClangScanDeps/logging-two-threads.c /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/build/tools/clang/test/ClangScanDeps/Output/logging-two-threads.c.tmp
# executed command: split-file /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/llvm-project/clang/test/ClangScanDeps/logging-two-threads.c /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/build/tools/clang/test/ClangScanDeps/Output/logging-two-threads.c.tmp
# note: command had no output on stdout or stderr
# RUN: at line 7
sed -e "s|DIR|/home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/build/tools/clang/test/ClangScanDeps/Output/logging-two-threads.c.tmp|g" /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/build/tools/clang/test/ClangScanDeps/Output/logging-two-threads.c.tmp/cdb.json.template > /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/build/tools/clang/test/ClangScanDeps/Output/logging-two-threads.c.tmp/cdb.json
# executed command: sed -e 's|DIR|/home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/build/tools/clang/test/ClangScanDeps/Output/logging-two-threads.c.tmp|g' /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/build/tools/clang/test/ClangScanDeps/Output/logging-two-threads.c.tmp/cdb.json.template
# note: command had no output on stdout or stderr
# RUN: at line 9
/home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/build/bin/clang-scan-deps -compilation-database /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/build/tools/clang/test/ClangScanDeps/Output/logging-two-threads.c.tmp/cdb.json    -format experimental-full -log-path=/home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/build/tools/clang/test/ClangScanDeps/Output/logging-two-threads.c.tmp/scan.log -j 2 -o /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/build/tools/clang/test/ClangScanDeps/Output/logging-two-threads.c.tmp/deps.json
# executed command: /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/build/bin/clang-scan-deps -compilation-database /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/build/tools/clang/test/ClangScanDeps/Output/logging-two-threads.c.tmp/cdb.json -format experimental-full -log-path=/home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/build/tools/clang/test/ClangScanDeps/Output/logging-two-threads.c.tmp/scan.log -j 2 -o /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/build/tools/clang/test/ClangScanDeps/Output/logging-two-threads.c.tmp/deps.json
# note: command had no output on stdout or stderr
# RUN: at line 13
/home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/build/bin/FileCheck /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/llvm-project/clang/test/ClangScanDeps/logging-two-threads.c --check-prefix=TU1 < /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/build/tools/clang/test/ClangScanDeps/Output/logging-two-threads.c.tmp/scan.log
# executed command: /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/build/bin/FileCheck /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/llvm-project/clang/test/ClangScanDeps/logging-two-threads.c --check-prefix=TU1
# note: command had no output on stdout or stderr
# RUN: at line 14
/home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/build/bin/FileCheck /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/llvm-project/clang/test/ClangScanDeps/logging-two-threads.c --check-prefix=TU2 < /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/build/tools/clang/test/ClangScanDeps/Output/logging-two-threads.c.tmp/scan.log
# executed command: /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/build/bin/FileCheck /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/llvm-project/clang/test/ClangScanDeps/logging-two-threads.c --check-prefix=TU2
# note: command had no output on stdout or stderr
# RUN: at line 24
grep -c "pcm_compile:" /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/build/tools/clang/test/ClangScanDeps/Output/logging-two-threads.c.tmp/scan.log | /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/build/bin/FileCheck /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/llvm-project/clang/test/ClangScanDeps/logging-two-threads.c --check-prefix=COMPILES
# executed command: grep -c pcm_compile: /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/build/tools/clang/test/ClangScanDeps/Output/logging-two-threads.c.tmp/scan.log
# note: command had no output on stdout or stderr
# executed command: /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/build/bin/FileCheck /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/llvm-project/clang/test/ClangScanDeps/logging-two-threads.c --check-prefix=COMPILES
# note: command had no output on stdout or stderr
# RUN: at line 25
grep -c "pcm_write:" /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/build/tools/clang/test/ClangScanDeps/Output/logging-two-threads.c.tmp/scan.log | /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/build/bin/FileCheck /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/llvm-project/clang/test/ClangScanDeps/logging-two-threads.c --check-prefix=PCMWRITES
# executed command: grep -c pcm_write: /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/build/tools/clang/test/ClangScanDeps/Output/logging-two-threads.c.tmp/scan.log
# note: command had no output on stdout or stderr
# executed command: /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/build/bin/FileCheck /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/llvm-project/clang/test/ClangScanDeps/logging-two-threads.c --check-prefix=PCMWRITES
# note: command had no output on stdout or stderr
# RUN: at line 26
grep -c "timestamp_write:" /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/build/tools/clang/test/ClangScanDeps/Output/logging-two-threads.c.tmp/scan.log | /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/build/bin/FileCheck /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/llvm-project/clang/test/ClangScanDeps/logging-two-threads.c --check-prefix=TSWRITES
# executed command: grep -c timestamp_write: /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/build/tools/clang/test/ClangScanDeps/Output/logging-two-threads.c.tmp/scan.log
# note: command had no output on stdout or stderr
# executed command: /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/build/bin/FileCheck /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/llvm-project/clang/test/ClangScanDeps/logging-two-threads.c --check-prefix=TSWRITES
# .---command stderr------------
# | /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/llvm-project/clang/test/ClangScanDeps/logging-two-threads.c:29:14: error: TSWRITES: expected string not found in input
# | // TSWRITES: {{^2$}}
# |              ^
...

```

</details>

https://github.com/llvm/llvm-project/pull/210564