SignalHandler_TEST is flaky on Windows

[azeey]

Environment

• OS Version: Ubuntu 24.04
• Source or binary build? source, gz-common6

Error Message

C:\J\workspace\gz_common-6-win\ws\gz-common\src\SignalHandler_TEST.cc:84
Expected equality of these values:
  15
  gHandler1Sig
    Which is: -1
Stacktrace
C:\J\workspace\gz_common-6-win\ws\gz-common\src\SignalHandler_TEST.cc:84
Expected equality of these values:
  15
  gHandler1Sig
    Which is: -1

[traversaro]

Interesting, I am experiencing the same failure in cross-compiled (where the tests are emulated by qemu) linux-aarch64 builds on conda-forge in https://dev.azure.com/conda-forge/feedstock-builds/_build/results?buildId=1040584&view=logs&j=bcfc29e7-7705-531c-c9b0-b095e11eba71&t=7ff00f50-b2a4-57aa-ed94-954260b92717 :

 17/110 Test  #17: UNIT_SignalHandler_TEST .................***Failed    0.23 sec
Running main() from /home/conda/feedstock_root/build_artifacts/gz-common6_1727615885025/work/test/gtest_vendor/src/gtest_main.cc
[==========] Running 6 tests from 1 test suite.
[----------] Global test environment set-up.
[----------] 6 tests from SignalHandler
[ RUN      ] SignalHandler.Single
/home/conda/feedstock_root/build_artifacts/gz-common6_1727615885025/work/src/SignalHandler_TEST.cc:84: Failure
Expected equality of these values:
  15
  gHandler1Sig
    Which is: -1
[  FAILED  ] SignalHandler.Single (56 ms)
[ RUN      ] SignalHandler.Multiple
[       OK ] SignalHandler.Multiple (12 ms)
[ RUN      ] SignalHandler.InitFailure
(2024-09-29 13:25:29.864) [error] [SignalHandler.cc:268] The SignalHandler was not initialized. Adding a callback will have no effect.
[       OK ] SignalHandler.InitFailure (12 ms)
[ RUN      ] SignalHandler.Thread
[       OK ] SignalHandler.Thread (9 ms)
[ RUN      ] SignalHandler.MultipleThreads
[       OK ] SignalHandler.MultipleThreads (9 ms)
[ RUN      ] SignalHandler.RapidFire
[       OK ] SignalHandler.RapidFire (18 ms)
[----------] 6 tests from SignalHandler (123 ms total)

[----------] Global test environment tear-down
[==========] 6 tests from 1 test suite ran. (130 ms total)
[  PASSED  ] 5 tests.
[  FAILED  ] 1 test, listed below:
[  FAILED  ] SignalHandler.Single

 1 FAILED TEST

        Start  18: check_UNIT_SignalHandler_TEST