Tracking issue to keep track of tests aren't hermetic

• [libc] port fpe and process-related unit test utils to hermetic mode #133925
• [libc][test] libc/test/UnitTest/RoundingModeUtils.cpp is not hermetic #135211
• [libc][test] libc/test/UnitTest/LibcTestMain.cpp should be hermetic #135213
• [libc][test] libc/test/UnitTest/LibcTest.cpp should be hermetic #135214
• [libc][test] libc/test/UnitTest/TestLogger.cpp should be hermetic #135215
• [libc][test] libc/test/UnitTest/MemoryMatcher.cpp should be hermetic #135216
• [libc][test] libc/test/UnitTest/CmakeFilePath.cpp should be hermetic #135217