Fix `FaultMaps` crash when the out streamer is reused
Summary:
Make sure the map is cleared before processing a new module. Similar to what is done on `StackMaps`.
This issue is similar to D38588, though this time for FaultMaps (on x86) rather than ARM/AArch64. Other than possible mixing of information between modules, the crash is caused by the pointers values in the map that was allocated by the bump pointer allocator that is unwinded when emitting the next file. This issue has been around since 3.8.
This issue is likely much harder to write a test for since AFAICT it requires emitting something much more compilcated (and possibly real code) instead of just some random bytes.
Reviewers: skatkov, sanjoy
Reviewed By: skatkov, sanjoy
Subscribers: sanjoy, aemerson, llvm-commits, kristof.beyls
Differential Revision: https://reviews.llvm.org/D38924
llvm-svn: 315990