[llvm] Add DebugSSAUpdater class to track debug value liveness (PR #135349)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `lldb-x86_64-debian` running on `lldb-x86_64-debian` while building `llvm` at step 6 "test".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/162/builds/31207

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

```
Step 6 (test) failure: build (failure)
...
PASS: lldb-api :: functionalities/breakpoint/breakpoint_callback_command_source/TestBreakpointCallbackCommandSource.py (523 of 3192)
PASS: lldb-api :: functionalities/memory/big-read/TestMemoryReadMaximumSize.py (524 of 3192)
PASS: lldb-api :: functionalities/memory/cache/TestMemoryCache.py (525 of 3192)
PASS: lldb-api :: functionalities/gdb_remote_client/TestRecognizeBreakpoint.py (526 of 3192)
PASS: lldb-api :: functionalities/postmortem/elf-core/gcore/TestGCore.py (527 of 3192)
PASS: lldb-api :: functionalities/gdb_remote_client/TestTargetXMLArch.py (528 of 3192)
PASS: lldb-api :: functionalities/load_lazy/TestLoadUsingLazyBind.py (529 of 3192)
PASS: lldb-api :: functionalities/postmortem/elf-core/thread_crash/TestLinuxCoreThreads.py (530 of 3192)
UNSUPPORTED: lldb-api :: functionalities/pre_run_dylibs/TestPreRunDylibs.py (531 of 3192)
UNRESOLVED: lldb-api :: functionalities/postmortem/netbsd-core/TestNetBSDCore.py (532 of 3192)
******************** TEST 'lldb-api :: functionalities/postmortem/netbsd-core/TestNetBSDCore.py' FAILED ********************
Script:
--
/usr/bin/python3 /home/worker/2.0.1/lldb-x86_64-debian/llvm-project/lldb/test/API/dotest.py -u CXXFLAGS -u CFLAGS --env LLVM_LIBS_DIR=/home/worker/2.0.1/lldb-x86_64-debian/build/./lib --env LLVM_INCLUDE_DIR=/home/worker/2.0.1/lldb-x86_64-debian/build/include --env LLVM_TOOLS_DIR=/home/worker/2.0.1/lldb-x86_64-debian/build/./bin --arch x86_64 --build-dir /home/worker/2.0.1/lldb-x86_64-debian/build/lldb-test-build.noindex --lldb-module-cache-dir /home/worker/2.0.1/lldb-x86_64-debian/build/lldb-test-build.noindex/module-cache-lldb/lldb-api --clang-module-cache-dir /home/worker/2.0.1/lldb-x86_64-debian/build/lldb-test-build.noindex/module-cache-clang/lldb-api --executable /home/worker/2.0.1/lldb-x86_64-debian/build/./bin/lldb --compiler /home/worker/2.0.1/lldb-x86_64-debian/build/./bin/clang --dsymutil /home/worker/2.0.1/lldb-x86_64-debian/build/./bin/dsymutil --make /usr/bin/gmake --llvm-tools-dir /home/worker/2.0.1/lldb-x86_64-debian/build/./bin --lldb-obj-root /home/worker/2.0.1/lldb-x86_64-debian/build/tools/lldb --lldb-libs-dir /home/worker/2.0.1/lldb-x86_64-debian/build/./lib --cmake-build-type Release -t /home/worker/2.0.1/lldb-x86_64-debian/llvm-project/lldb/test/API/functionalities/postmortem/netbsd-core -p TestNetBSDCore.py
--
Exit Code: -6

Command Output (stdout):
--
lldb version 22.0.0git (https://github.com/llvm/llvm-project.git revision 3946c5061d708b1e7604db63e9b604cb0fce7dd6)
  clang revision 3946c5061d708b1e7604db63e9b604cb0fce7dd6
  llvm revision 3946c5061d708b1e7604db63e9b604cb0fce7dd6
Skipping the following test categories: ['libc++', 'msvcstl', 'dsym', 'gmodules', 'debugserver', 'objc']

--
Command Output (stderr):
--
Change dir to: /home/worker/2.0.1/lldb-x86_64-debian/llvm-project/lldb/test/API/functionalities/postmortem/netbsd-core
runCmd: settings clear --all

output: 

runCmd: settings set symbols.enable-external-lookup false

output: 

runCmd: settings set target.inherit-tcc true

output: 

runCmd: settings set target.disable-aslr false

output: 

runCmd: settings set target.detach-on-error false

output: 

runCmd: settings set target.auto-apply-fixits false

```

</details>

https://github.com/llvm/llvm-project/pull/135349