[clang] [clang][AST] Add 'IgnoreTemplateParmDepth' to structural equivalence cache (PR #115518)

[Balázs Kéri via cfe-commits]

balazske wrote:

Another possible solution: Use two `NonEquivalentDecls` sets, one for `IgnoreTemplateParmDepth` = true and one for false. This may use less memory (no rarely used third value in the key) but requires more code changes. Probably use these two caches only in `ASTImporter` where the correct one can be passed to `StructuralEquivalenceContext`.

https://github.com/llvm/llvm-project/pull/115518