[clang] [clang] Reduce the small vector size for DeclTypeInfo. (PR #148788)

[Aaron Ballman via cfe-commits]

https://github.com/AaronBallman approved this pull request.

LGTM! 8 declarator chunks is actually quite a bit, I suspect 4 is a more sensible default for the average TU. 2 might be a bit too few for what I'd suspect is the average use case.

https://github.com/llvm/llvm-project/pull/148788