[llvm] [LLVM][PDB] Use IsUnsigned flag for APInt correctly (PR #131598)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `clang-ppc64le-rhel` running on `ppc64le-clang-rhel-test` while building `llvm` at step 7 "test-build-unified-tree-check-all".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/145/builds/5745

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

```
Step 7 (test-build-unified-tree-check-all) failure: test (failure)
...
0.628 [1/3/2] Building CXX object compiler-rt/lib/ubsan/CMakeFiles/RTUbsan_dynamic_version_script_dummy.powerpc64le.dir/dummy.cpp.o
0.930 [0/3/3] Linking CXX shared library /home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-rhel-test/clang-ppc64le-rhel/build/lib/clang/21/lib/powerpc64le-unknown-linux-gnu/libclang_rt.ubsan_standalone.so
0.954 [0/2/4] Linking CXX shared library /home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-rhel-test/clang-ppc64le-rhel/build/lib/clang/21/lib/powerpc64le-unknown-linux-gnu/libclang_rt.asan.so
1.541 [0/1/5] Generating /home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-rhel-test/clang-ppc64le-rhel/build/compile_commands.json
24.361 [5/6/1213] Linking CXX executable unittests/Target/AMDGPU/AMDGPUTests
24.898 [4/5/1214] cd /home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-rhel-test/clang-ppc64le-rhel/build/runtimes/runtimes-bins && /home/buildbots/llvm-external-buildbots/cmake-3.31.2/bin/cmake --build /home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-rhel-test/clang-ppc64le-rhel/build/runtimes/runtimes-bins/ --target runtimes-test-depends --config Release
ninja: no work to do.
24.962 [3/5/1215] No install step for 'runtimes'
24.984 [2/5/1217] Completed 'runtimes'
25.251 [2/4/1218] Building CXX object unittests/DebugInfo/PDB/CMakeFiles/DebugInfoPDBTests.dir/PDBVariantTest.cpp.o
FAILED: unittests/DebugInfo/PDB/CMakeFiles/DebugInfoPDBTests.dir/PDBVariantTest.cpp.o 
ccache /home/buildbots/llvm-external-buildbots/clang.19.1.7/bin/clang++ --gcc-toolchain=/gcc-toolchain/usr -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/home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-rhel-test/clang-ppc64le-rhel/build/unittests/DebugInfo/PDB -I/home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-rhel-test/clang-ppc64le-rhel/llvm-project/llvm/unittests/DebugInfo/PDB -I/home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-rhel-test/clang-ppc64le-rhel/build/include -I/home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-rhel-test/clang-ppc64le-rhel/llvm-project/llvm/include -I/home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-rhel-test/clang-ppc64le-rhel/llvm-project/third-party/unittest/googletest/include -I/home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-rhel-test/clang-ppc64le-rhel/llvm-project/third-party/unittest/googlemock/include -fPIC -fno-semantic-interposition -fvisibility-inlines-hidden -Werror -Werror=date-time -Werror=unguarded-availability-new -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wmissing-field-initializers -pedantic -Wno-long-long -Wc++98-compat-extra-semi -Wimplicit-fallthrough -Wcovered-switch-default -Wno-noexcept-type -Wnon-virtual-dtor -Wdelete-non-virtual-dtor -Wsuggest-override -Wstring-conversion -Wmisleading-indentation -Wctad-maybe-unsupported -fdiagnostics-color -ffunction-sections -fdata-sections -O3 -DNDEBUG -std=c++17  -Wno-variadic-macros -Wno-gnu-zero-variadic-macro-arguments -fno-exceptions -funwind-tables -fno-rtti -UNDEBUG -Wno-suggest-override -MD -MT unittests/DebugInfo/PDB/CMakeFiles/DebugInfoPDBTests.dir/PDBVariantTest.cpp.o -MF unittests/DebugInfo/PDB/CMakeFiles/DebugInfoPDBTests.dir/PDBVariantTest.cpp.o.d -o unittests/DebugInfo/PDB/CMakeFiles/DebugInfoPDBTests.dir/PDBVariantTest.cpp.o -c /home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-rhel-test/clang-ppc64le-rhel/llvm-project/llvm/unittests/DebugInfo/PDB/PDBVariantTest.cpp
/home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-rhel-test/clang-ppc64le-rhel/llvm-project/llvm/unittests/DebugInfo/PDB/PDBVariantTest.cpp:40:50: error: passing no argument for the '...' parameter of a variadic macro is a C++20 extension [-Werror,-Wc++20-extensions]
   40 | TYPED_TEST_SUITE(PDBVariantIntegerTest, TestTypes);
      |                                                  ^
/home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-rhel-test/clang-ppc64le-rhel/llvm-project/third-party/unittest/googletest/include/gtest/gtest-typed-test.h:191:9: note: macro 'TYPED_TEST_SUITE' defined here
  191 | #define TYPED_TEST_SUITE(CaseName, Types, ...)                          \
      |         ^
1 error generated.
26.077 [2/3/1219] Building CXX object unittests/DebugInfo/PDB/CMakeFiles/DebugInfoPDBTests.dir/PDBApiTest.cpp.o
26.865 [2/2/1220] Building CXX object unittests/DebugInfo/PDB/CMakeFiles/DebugInfoPDBTests.dir/NativeSessionTest.cpp.o
27.035 [2/1/1221] Building CXX object unittests/DebugInfo/PDB/CMakeFiles/DebugInfoPDBTests.dir/NativeSymbolReuseTest.cpp.o
ninja: build stopped: subcommand failed.

```

</details>

https://github.com/llvm/llvm-project/pull/131598