[clang] [Clang][Parser] Don't always destroy template annotations at the end of a declaration (PR #89494)

[Aaron Ballman via cfe-commits]

AaronBallman wrote:

On reflection, I am still happy enough with this approach. @cor3ntin's observation that we could remove the call to `MaybeDestroyTemplateIds()` so that we only destroy at the end of top-level decls and member specifications would work, but I think there arern was largely around the extra complexity of the current approach, but I think the complexity here is reasonably well-contained, and it doesn't seem to have any negative impact on performance (http://llvm-compile-time-tracker.com/compare.php?from=304dfe10bd96ef8badd53d4796bba070cc8d30dc&to=8ab3caf4d3acef29f373e09bc6a0ac459918930e&stat=instructions:u)

https://github.com/llvm/llvm-project/pull/89494