[clang] [Clang][CodeGen] Emit “trap reasons” on UBSan traps (PR #145967)

[Vitaly Buka via cfe-commits]

vitalybuka wrote:

> There is still one test case that fails: `cfi-check-fail-debuginfo.c`. From the crash report, I thought it was due to double wrapping, so I initially added a guard to prevent that, leading the test case to pass. Upon internal discussion, the guard has since been removed because double wrapping may be intended behavior. Crash report is left in the comments.

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https://github.com/llvm/llvm-project/pull/145967