[clang] [Clang] Fixed a crash when instantiating an invalid out-of-line static data member definition in a local class (PR #196772)

[Oliver Hunt via cfe-commits]

ojhunt wrote:

@TPPPP72 the regression was a failure yes, but did you make sure it wasn't your original change exposing a different underlying problem? e.g. a path that isn't mishandling an invalid decl. I know there are many ways in which we end up with invalid declarations not being marked as invalid, while maintaining correct behavior because even if we don't mark the relevant decls as invalid we've generated an error, which kills the build.

https://github.com/llvm/llvm-project/pull/196772