[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 `clang-cmake-x86_64-avx512-linux` running on `avx512-intel64` while building `llvm` at step 7 "ninja check 1".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/133/builds/13413

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

```
Step 7 (ninja check 1) failure: stage 1 checked (failure)
...
[43/92] Performing build step for 'runtimes'
[1/3] Building CXX object compiler-rt/lib/memprof/CMakeFiles/RTMemprof_dynamic_version_script_dummy.x86_64.dir/dummy.cpp.o
[2/3] Linking CXX shared library /localdisk2/buildbot/llvm-worker/clang-cmake-x86_64-avx512-linux/stage1/lib/clang/21/lib/x86_64-unknown-linux-gnu/libclang_rt.memprof.so
[3/3] Generating /localdisk2/buildbot/llvm-worker/clang-cmake-x86_64-avx512-linux/stage1/compile_commands.json
[44/92] cd /localdisk2/buildbot/llvm-worker/clang-cmake-x86_64-avx512-linux/stage1/runtimes/runtimes-bins && /usr/bin/cmake --build /localdisk2/buildbot/llvm-worker/clang-cmake-x86_64-avx512-linux/stage1/runtimes/runtimes-bins/ --target runtimes-test-depends --config Release
ninja: no work to do.
[45/92] No install step for 'runtimes'
[47/92] Completed 'runtimes'
[48/92] Linking CXX executable unittests/Target/TargetMachineCTests
[49/92] Building CXX object unittests/Support/CMakeFiles/SupportTests.dir/YAMLIOTest.cpp.o
FAILED: unittests/Support/CMakeFiles/SupportTests.dir/YAMLIOTest.cpp.o 
/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/localdisk2/buildbot/llvm-worker/clang-cmake-x86_64-avx512-linux/stage1/unittests/Support -I/localdisk2/buildbot/llvm-worker/clang-cmake-x86_64-avx512-linux/llvm/llvm/unittests/Support -I/localdisk2/buildbot/llvm-worker/clang-cmake-x86_64-avx512-linux/stage1/include -I/localdisk2/buildbot/llvm-worker/clang-cmake-x86_64-avx512-linux/llvm/llvm/include -I/localdisk2/buildbot/llvm-worker/clang-cmake-x86_64-avx512-linux/llvm/third-party/unittest/googletest/include -I/localdisk2/buildbot/llvm-worker/clang-cmake-x86_64-avx512-linux/llvm/third-party/unittest/googlemock/include -march=cascadelake -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 -Wctad-maybe-unsupported -fdiagnostics-color -ffunction-sections -fdata-sections -O3 -DNDEBUG -std=c++17  -Wno-dangling-else -Wno-variadic-macros -fno-exceptions -funwind-tables -fno-rtti -UNDEBUG -Wno-suggest-override -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 /localdisk2/buildbot/llvm-worker/clang-cmake-x86_64-avx512-linux/llvm/llvm/unittests/Support/YAMLIOTest.cpp
/localdisk2/buildbot/llvm-worker/clang-cmake-x86_64-avx512-linux/llvm/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> {
      |                    ^~~~~~~~~~~~~~~~
[50/92] Linking CXX executable unittests/CodeGen/GlobalISel/GlobalISelTests
[51/92] Linking CXX executable unittests/MIR/MIRTests
[52/92] Linking CXX executable unittests/Transforms/Instrumentation/InstrumentationTests
[53/92] Linking CXX executable unittests/Frontend/LLVMFrontendTests
[54/92] Linking CXX executable unittests/ExecutionEngine/Orc/OrcJITTests
[55/92] Linking CXX executable unittests/tools/llvm-mca/LLVMMCATests
[56/92] Linking CXX executable unittests/DebugInfo/LogicalView/DebugInfoLogicalViewTests
[57/92] Linking CXX executable tools/clang/unittests/Serialization/SerializationTests
[58/92] Linking CXX executable unittests/Passes/Plugins/PluginsTests
[59/92] Linking CXX executable unittests/Transforms/Utils/UtilsTests
[60/92] Linking CXX executable unittests/tools/llvm-exegesis/LLVMExegesisTests
[61/92] Linking CXX executable unittests/MI/MITests
[62/92] Linking CXX executable tools/clang/unittests/Lex/LexTests
[63/92] Linking CXX executable tools/clang/unittests/Analysis/ClangAnalysisTests
[64/92] Linking CXX executable unittests/Transforms/Coroutines/CoroTests
[65/92] Linking CXX executable unittests/DebugInfo/DWARF/DebugInfoDWARFTests
[66/92] Linking CXX executable tools/clang/unittests/AST/ByteCode/InterpTests
[67/92] Linking CXX executable unittests/Transforms/Scalar/ScalarTests
[68/92] Linking CXX executable tools/clang/unittests/CrossTU/CrossTUTests
[69/92] Linking CXX executable tools/clang/unittests/Tooling/Syntax/SyntaxTests
[70/92] Linking CXX executable unittests/Passes/PassBuilderBindings/PassesBindingsTests
[71/92] Linking CXX executable tools/clang/unittests/ASTMatchers/ASTMatchersTests
[72/92] Linking CXX executable tools/clang/unittests/ASTMatchers/Dynamic/DynamicASTMatchersTests
[73/92] Linking CXX executable tools/clang/unittests/Sema/SemaTests
[74/92] Linking CXX executable unittests/IR/IRTests
[75/92] Linking CXX executable unittests/ExecutionEngine/MCJIT/MCJITTests
[76/92] Linking CXX executable tools/clang/unittests/Support/ClangSupportTests
[77/92] Linking CXX executable tools/clang/unittests/Index/IndexTests
[78/92] Linking CXX executable unittests/Analysis/AnalysisTests
[79/92] Linking CXX executable tools/clang/unittests/Rewrite/RewriteTests
[80/92] Linking CXX executable unittests/Target/X86/X86Tests
[81/92] Linking CXX executable unittests/CodeGen/CodeGenTests
[82/92] Linking CXX executable tools/clang/unittests/AST/ASTTests
[83/92] Linking CXX executable tools/clang/unittests/Analysis/FlowSensitive/ClangAnalysisFlowSensitiveTests

```

</details>

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