[clang] [llvm] [mlir] [Support] Validate number of arguments passed to formatv() (PR #105745)

[LLVM Continuous Integration via cfe-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `llvm-clang-x86_64-win-fast` running on `as-builder-3` while building `clang,llvm,mlir` at step 7 "test-build-unified-tree-check-llvm-unit".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/2/builds/5504

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

```
Step 7 (test-build-unified-tree-check-llvm-unit) failure: test (failure)
******************** TEST 'LLVM-Unit :: Support/./SupportTests.exe/56/85' FAILED ********************
Script(shard):
--
GTEST_OUTPUT=json:C:\buildbot\as-builder-3\llvm-clang-x86_64-win-fast\build\unittests\Support\.\SupportTests.exe-LLVM-Unit-11744-56-85.json GTEST_SHUFFLE=0 GTEST_TOTAL_SHARDS=85 GTEST_SHARD_INDEX=56 C:\buildbot\as-builder-3\llvm-clang-x86_64-win-fast\build\unittests\Support\.\SupportTests.exe
--

Script:
--
C:\buildbot\as-builder-3\llvm-clang-x86_64-win-fast\build\unittests\Support\.\SupportTests.exe --gtest_filter=FormatVariadicTest.Validate
--
C:\buildbot\as-builder-3\llvm-clang-x86_64-win-fast\llvm-project\llvm\unittests\Support\FormatVariadicTest.cpp(716): error: Value of: Str
Expected: has substring "Unexpected number of arguments"
  Actual: "1"

C:\buildbot\as-builder-3\llvm-clang-x86_64-win-fast\llvm-project\llvm\unittests\Support\FormatVariadicTest.cpp(719): error: Value of: Str
Expected: has substring "eplacement indices have holes"
  Actual: "1 3"


C:\buildbot\as-builder-3\llvm-clang-x86_64-win-fast\llvm-project\llvm\unittests\Support\FormatVariadicTest.cpp:716
Value of: Str
Expected: has substring "Unexpected number of arguments"
  Actual: "1"

C:\buildbot\as-builder-3\llvm-clang-x86_64-win-fast\llvm-project\llvm\unittests\Support\FormatVariadicTest.cpp:719
Value of: Str
Expected: has substring "eplacement indices have holes"
  Actual: "1 3"



********************


```

</details>

https://github.com/llvm/llvm-project/pull/105745