[clang] [clang-tools-extra] [flang] Reapply "[clang] Extend diagnose_if to accept more detailed warning information (#70976)" (PR #108453)

[Florian Mayer via cfe-commits]

fmayer wrote:

This caused a UBSan violation: 
```
[----------] 1 test from ConfigCompileTests
[ RUN      ] ConfigCompileTests.DiagnosticSuppression
Config fragment: compiling <unknown>:0 -> 0x00007B8366E2F7D8 (trusted=false)
/usr/local/google/home/fmayer/large/llvm-project/llvm/include/llvm/ADT/IntrusiveRefCntPtr.h:203:33: runtime error: reference binding to null pointer of type 'clang::DiagnosticIDs'
SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior /usr/local/google/home/fmayer/large/llvm-project/llvm/include/llvm/ADT/IntrusiveRefCntPtr.h:203:33 

--
exit: 1
--
```

https://github.com/llvm/llvm-project/pull/108453