[clang] [clang][Sema] Improve error recovery for id-expressions referencing invalid decls (PR #81662)

[Nathan Ridge via cfe-commits]

HighCommander4 wrote:

Changing to Draft status as CI is showing some test failures that I will need to investigate:

```
Failed Tests (4):
  Clang :: OpenMP/nvptx_unsupported_type_messages.cpp
  Clang :: SemaCXX/constant-expression-cxx11.cpp
  Clang :: SemaCXX/cxx2b-consteval-if.cpp
  Clang :: SemaCXX/deduced-return-type-cxx14.cpp
```

https://github.com/llvm/llvm-project/pull/81662