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

[Younan Zhang via cfe-commits]

zyn0217 wrote:

> If we remove MaybeDestroyTemplateIds(); in ParseStatementOrDeclaration, does it fix the bug, and does it actually impact performance?

It fixes the bug; however, I'm afraid we would also lose the chance to optimize the following:
```cpp
void foo() {
  auto generic = []<class T>() {}; // 1'
  auto generic_2 = []<class U, class V>() {}; // 2'
  // ... and many more ...
} // We'd remove `T`, `U` and `V` here rather than at 1' and 2'.
```

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