[llvm] [NFCI][Globals] In GlobalObjects::setSectionPrefix, do conditional update if existing prefix is not equivalent to the new one. Returns whether prefix changed. (PR #158460)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `clang-with-lto-ubuntu` running on `as-worker-91` while building `llvm` at step 7 "test-stage1-compiler".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/49/builds/2239

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

```
Step 7 (test-stage1-compiler) failure: build (failure)
...
llvm-lit: /home/buildbot/as-worker-91/clang-with-lto-ubuntu/llvm-project/llvm/utils/lit/lit/llvm/config.py:530: note: using ld64.lld: /home/buildbot/as-worker-91/clang-with-lto-ubuntu/build/stage1/bin/ld64.lld
llvm-lit: /home/buildbot/as-worker-91/clang-with-lto-ubuntu/llvm-project/llvm/utils/lit/lit/llvm/config.py:530: note: using wasm-ld: /home/buildbot/as-worker-91/clang-with-lto-ubuntu/build/stage1/bin/wasm-ld
llvm-lit: /home/buildbot/as-worker-91/clang-with-lto-ubuntu/build/stage1/utils/lit/tests/lit.cfg:111: warning: Setting a timeout per test not supported. Requires the Python psutil module but it could not be found. Try installing it via pip or via your operating system's package manager.
 Some tests will be skipped and the --timeout command line argument will not work.
llvm-lit: /home/buildbot/as-worker-91/clang-with-lto-ubuntu/llvm-project/llvm/utils/lit/lit/llvm/config.py:530: note: using ld.lld: /home/buildbot/as-worker-91/clang-with-lto-ubuntu/build/stage1/bin/ld.lld
llvm-lit: /home/buildbot/as-worker-91/clang-with-lto-ubuntu/llvm-project/llvm/utils/lit/lit/llvm/config.py:530: note: using lld-link: /home/buildbot/as-worker-91/clang-with-lto-ubuntu/build/stage1/bin/lld-link
llvm-lit: /home/buildbot/as-worker-91/clang-with-lto-ubuntu/llvm-project/llvm/utils/lit/lit/llvm/config.py:530: note: using ld64.lld: /home/buildbot/as-worker-91/clang-with-lto-ubuntu/build/stage1/bin/ld64.lld
llvm-lit: /home/buildbot/as-worker-91/clang-with-lto-ubuntu/llvm-project/llvm/utils/lit/lit/llvm/config.py:530: note: using wasm-ld: /home/buildbot/as-worker-91/clang-with-lto-ubuntu/build/stage1/bin/wasm-ld
-- Testing: 87367 tests, 72 workers --
Testing:  0.. 10.. 20.. 30.. 40.. 50.
FAIL: LLVM :: CodeGen/X86/memcmp-pgso-x32.ll (50466 of 87367)
******************** TEST 'LLVM :: CodeGen/X86/memcmp-pgso-x32.ll' FAILED ********************
Exit Code: 1

Command Output (stdout):
--
# RUN: at line 2
/home/buildbot/as-worker-91/clang-with-lto-ubuntu/build/stage1/bin/llc < /home/buildbot/as-worker-91/clang-with-lto-ubuntu/llvm-project/llvm/test/CodeGen/X86/memcmp-pgso-x32.ll -mtriple=i686-unknown-unknown -mattr=cmov | /home/buildbot/as-worker-91/clang-with-lto-ubuntu/build/stage1/bin/FileCheck /home/buildbot/as-worker-91/clang-with-lto-ubuntu/llvm-project/llvm/test/CodeGen/X86/memcmp-pgso-x32.ll --check-prefixes=X86,X86-NOSSE
# executed command: /home/buildbot/as-worker-91/clang-with-lto-ubuntu/build/stage1/bin/llc -mtriple=i686-unknown-unknown -mattr=cmov
# executed command: /home/buildbot/as-worker-91/clang-with-lto-ubuntu/build/stage1/bin/FileCheck /home/buildbot/as-worker-91/clang-with-lto-ubuntu/llvm-project/llvm/test/CodeGen/X86/memcmp-pgso-x32.ll --check-prefixes=X86,X86-NOSSE
# .---command stderr------------
# | /home/buildbot/as-worker-91/clang-with-lto-ubuntu/llvm-project/llvm/test/CodeGen/X86/memcmp-pgso-x32.ll:83:13: error: X86-NEXT: expected string not found in input
# | ; X86-NEXT: jne .LBB4_3
# |             ^
# | <stdin>:75:15: note: scanning from here
# |  cmpw %si, %dx
# |               ^
# | <stdin>:76:2: note: possible intended match here
# |  jne .LBB4_1
# |  ^
# | /home/buildbot/as-worker-91/clang-with-lto-ubuntu/llvm-project/llvm/test/CodeGen/X86/memcmp-pgso-x32.ll:173:13: error: X86-NEXT: expected string not found in input
# | ; X86-NEXT: jne .LBB9_3
# |             ^
# | <stdin>:167:17: note: scanning from here
# |  cmpl %esi, %edx
# |                 ^
# | <stdin>:168:2: note: possible intended match here
# |  jne .LBB9_1
# |  ^
# | /home/buildbot/as-worker-91/clang-with-lto-ubuntu/llvm-project/llvm/test/CodeGen/X86/memcmp-pgso-x32.ll:219:13: error: X86-NEXT: expected string not found in input
# | ; X86-NEXT: jne .LBB11_2
# |             ^
# | <stdin>:214:17: note: scanning from here
# |  cmpl %edx, %ecx
# |                 ^
# | <stdin>:215:2: note: possible intended match here
# |  jne .LBB11_1
# |  ^
# | 

```

</details>

https://github.com/llvm/llvm-project/pull/158460