[clang] [clang][ObjectiveC] Fix Parsing Types with the `::` Optional Scope Specifier (PR #119908)

[Qiongsi Wu via cfe-commits]

qiongsiwu wrote:

Thanks for the feedback everyone! The PR is updated to address the review comments. 

- A test is added to cover Objective-C++. https://github.com/llvm/llvm-project/pull/119908/files#diff-7f1cce2d0397139fc73d3615c8249ac9530082aa707868c0e921f53daf594384R1 I am not sure if this is sufficient so please provide feedback. 
- The Objective-C test is revised to cover the optional scope specifier on variables (in addition to parameters) https://github.com/llvm/llvm-project/pull/119908/files#diff-0c0e8844905a75c581903811a694e614f49b2945e2254a76bb5a215443028554R11. 
- The release note is updated https://github.com/llvm/llvm-project/pull/119908/files#diff-ec770381d76c859f5f572db789175fe44410a72608f58ad5dbb14335ba56eb97R678. 

https://github.com/llvm/llvm-project/pull/119908