Debug build on Mac OS X: super-rare bug in test mutex lock failed: Invalid argument

[maxgolov]

Mac OS X debug build - functional test is hitting this issue:

[ RUN      ] APITest.LogManager_Reinitialize_UploadNow
[       OK ] APITest.LogManager_Reinitialize_UploadNow (4830 ms)
[ RUN      ] APITest.LogManager_BadStoragePath_Test
libc++abi.dylib: terminating with uncaught exception of type std::__1::system_error: mutex lock failed: Invalid argument
./build-tests.sh: line 9:  4799 Abort trap: 6           ./tests/functests/FuncTests
##[error]Process completed with exit code 134.

I have seen it twice across many runs during the last couple-to-three months. It is not clear if it's the compiler upgrade, or timing, or some left-over from the previous UploadNow test. We need to monitor it.

[bliptec]

This looks like a manifestation of the issue fixed in #382 so I'll go ahead and close it. Typically the mutuxes would catch the use-after free when worker thread tasks executed after the SDK already began tearing down the telemetry system