Signal handler is not async safe

[rossmacgregor]

Signal hander should be async safe to avoid deadlocks. Thread sanitizer is reporting that new is being calling inside the signal handler.

WARNING: ThreadSanitizer: signal-unsafe call inside of a signal (pid=25902)
#0 operator new(unsigned long) :0 (OamTest+0x0000000f26cd)
#1 void std::__1::vector<Test::LogMessage, std::__1::allocatorTest::LogMessage >::__push_back_slow_pathTest::LogMessage(Test::LogMessage&&) :0 (OamTest+0x000000291ac7)
#2 Test::TestLogWriter::WriteInfo(std::__1::basic_string<char, std::__1::char_traits, std::_1::allocator > const&, char const, int) :0 (OamTest+0x00000028f20a)
#3 (anonymous namespace)::SignalHandler(int) :0 (OamTest+0x00000028c2d9)
#4 _tsan::CallUserSignalHandler(tsan::ThreadState, bool, bool, int, my_siginfo_t, void) :0 (OamTest+0x0000000ff381)