[llvm] [SandboxVec] Add region-from-bbs helper pass (PR #130153)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `llvm-nvptx64-nvidia-win` running on `as-builder-8` while building `llvm` at step 7 "test-build-unified-tree-check-llvm".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/155/builds/7310

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

```
Step 7 (test-build-unified-tree-check-llvm) failure: test (failure)
******************** TEST 'LLVM-Unit :: Support/./SupportTests.exe/49/87' FAILED ********************
Script(shard):
--
GTEST_OUTPUT=json:C:\buildbot\as-builder-8\llvm-nvptx64-nvidia-win\build\unittests\Support\.\SupportTests.exe-LLVM-Unit-17988-49-87.json GTEST_SHUFFLE=0 GTEST_TOTAL_SHARDS=87 GTEST_SHARD_INDEX=49 C:\buildbot\as-builder-8\llvm-nvptx64-nvidia-win\build\unittests\Support\.\SupportTests.exe
--

Note: This is test shard 50 of 87.

[==========] Running 16 tests from 16 test suites.

[----------] Global test environment set-up.

[----------] 1 test from T2EEBuildAttr

[ RUN      ] T2EEBuildAttr.testBuildAttr

[       OK ] T2EEBuildAttr.testBuildAttr (0 ms)

[----------] 1 test from T2EEBuildAttr (0 ms total)



[----------] 1 test from Caching

[ RUN      ] Caching.Normal

C:\buildbot\as-builder-8\llvm-nvptx64-nvidia-win\llvm-project\llvm\unittests\Support\Caching.cpp(58): error: Value of: bool(FileOrErr)

  Actual: false

Expected: true



Expected<T> must be checked before access or destruction.

Unchecked Expected<T> contained error:

no such file or directory: LLVMTestCache: Can't get a temporary fileException Code: 0x80000003

 #0 0x00007ff773c2d685 (C:\buildbot\as-builder-8\llvm-nvptx64-nvidia-win\build\unittests\Support\SupportTests.exe+0x4fd685)

 #1 0x00007ffb8044d88d (C:\Windows\System32\ucrtbase.dll+0x6d88d)

 #2 0x00007ffb8044e761 (C:\Windows\System32\ucrtbase.dll+0x6e761)

 #3 0x00007ff773812614 (C:\buildbot\as-builder-8\llvm-nvptx64-nvidia-win\build\unittests\Support\SupportTests.exe+0xe2614)

 #4 0x00007ff773836ce6 (C:\buildbot\as-builder-8\llvm-nvptx64-nvidia-win\build\unittests\Support\SupportTests.exe+0x106ce6)

...

```

</details>

https://github.com/llvm/llvm-project/pull/130153