[clang] [Clang] Repair the function "rParenEndsCast" to make incorrect judgments in template variable cases (PR #120904)

[Owen Pan via cfe-commits]

https://github.com/owenca requested changes to this pull request.

Please run `ninja FormatTests` before submitting the patch. It fails a few unit tests before crashing.

https://github.com/llvm/llvm-project/pull/120904