[clang] [clang] Reduce LateInstantiatedAttrVec vector default size. (PR #142840)

[Aaron Ballman via cfe-commits]

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

LGTM, wow, that's a really nice win for such an easy change. Thank you!

https://github.com/llvm/llvm-project/pull/142840