[llvm] [YAML][NFC] precommit wrong test case (PR #131782)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `ml-opt-devrel-x86-64` running on `ml-opt-devrel-x86-64-b2` while building `llvm` at step 6 "test-build-unified-tree-check-all".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/175/builds/15639

<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)
...
5.609 [2/20/732] Linking CXX executable unittests/tools/llvm-profdata/LLVMProfdataTests
5.661 [2/19/733] Linking CXX executable unittests/Transforms/Vectorize/SandboxVectorizer/SandboxVectorizerTests
5.686 [2/18/734] Linking CXX executable unittests/Transforms/Vectorize/VectorizeTests
6.075 [2/17/735] Linking CXX executable unittests/Target/AMDGPU/AMDGPUTests
6.496 [2/16/736] Linking CXX executable unittests/Target/X86/X86Tests
6.552 [2/15/737] Linking CXX executable unittests/tools/llvm-cfi-verify/CFIVerifyTests
6.553 [2/14/738] Linking CXX executable unittests/Transforms/Coroutines/CoroTests
6.601 [2/13/739] Linking CXX executable unittests/Transforms/Instrumentation/InstrumentationTests
7.046 [2/12/740] Linking CXX executable unittests/Transforms/Utils/UtilsTests
7.093 [2/11/741] Building CXX object unittests/Support/CMakeFiles/SupportTests.dir/YAMLIOTest.cpp.o
FAILED: unittests/Support/CMakeFiles/SupportTests.dir/YAMLIOTest.cpp.o 
ccache /usr/bin/c++ -DGTEST_HAS_RTTI=0 -DLLVM_BUILD_STATIC -D_DEBUG -D_GLIBCXX_ASSERTIONS -D_GNU_SOURCE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -I/b/ml-opt-devrel-x86-64-b1/build/unittests/Support -I/b/ml-opt-devrel-x86-64-b1/llvm-project/llvm/unittests/Support -I/var/lib/buildbot/.local/lib/python3.7/site-packages/tensorflow/include -I/b/ml-opt-devrel-x86-64-b1/build/include -I/b/ml-opt-devrel-x86-64-b1/llvm-project/llvm/include -I/b/ml-opt-devrel-x86-64-b1/llvm-project/third-party/unittest/googletest/include -I/b/ml-opt-devrel-x86-64-b1/llvm-project/third-party/unittest/googlemock/include -fPIC -fno-semantic-interposition -fvisibility-inlines-hidden -Werror=date-time -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wno-missing-field-initializers -pedantic -Wno-long-long -Wimplicit-fallthrough -Wno-uninitialized -Wno-nonnull -Wno-class-memaccess -Wno-redundant-move -Wno-pessimizing-move -Wno-noexcept-type -Wdelete-non-virtual-dtor -Wsuggest-override -Wno-comment -Wno-misleading-indentation -fdiagnostics-color -ffunction-sections -fdata-sections -O3 -DNDEBUG  -Wno-dangling-else -Wno-variadic-macros -fno-exceptions -funwind-tables -fno-rtti -UNDEBUG -Wno-suggest-override -std=c++17 -MD -MT unittests/Support/CMakeFiles/SupportTests.dir/YAMLIOTest.cpp.o -MF unittests/Support/CMakeFiles/SupportTests.dir/YAMLIOTest.cpp.o.d -o unittests/Support/CMakeFiles/SupportTests.dir/YAMLIOTest.cpp.o -c /b/ml-opt-devrel-x86-64-b1/llvm-project/llvm/unittests/Support/YAMLIOTest.cpp
/b/ml-opt-devrel-x86-64-b1/llvm-project/llvm/unittests/Support/YAMLIOTest.cpp:1280:20: error: explicit specialization of ‘template<class T> struct llvm::yaml::MappingTraits’ outside its namespace must use a nested-name-specifier [-fpermissive]
 1280 | template <> struct MappingTraits<V> {
      |                    ^~~~~~~~~~~~~~~~
7.147 [2/10/742] Linking CXX executable unittests/CodeGen/CodeGenTests
7.459 [2/9/743] Linking CXX executable unittests/Transforms/Scalar/ScalarTests
7.485 [2/8/744] Linking CXX executable unittests/tools/llvm-mca/LLVMMCATests
7.536 [2/7/745] Linking CXX executable unittests/MIR/MIRTests
7.545 [2/6/746] Linking CXX executable unittests/CodeGen/GlobalISel/GlobalISelTests
7.627 [2/5/747] Linking CXX executable unittests/DebugInfo/LogicalView/DebugInfoLogicalViewTests
7.667 [2/4/748] Linking CXX executable unittests/DebugInfo/DWARF/DebugInfoDWARFTests
7.699 [2/3/749] Linking CXX executable unittests/MI/MITests
7.953 [2/2/750] Linking CXX executable unittests/Target/TargetMachineCTests
8.745 [2/1/751] Linking CXX executable unittests/tools/llvm-exegesis/LLVMExegesisTests
ninja: build stopped: subcommand failed.

```

</details>

https://github.com/llvm/llvm-project/pull/131782