[llvm] [AggressiveInstCombine] Fix crash when folding consecutive loads into a type smaller than the combined load (PR #207229)

[Kyungtak Woo via llvm-commits]

kevinwkt wrote:

I rejected the fold early when the combined load size exceeds the target type size because doing so prevents invalid ZExt instructions, as @dtcxzyw mentioned. Will re-request approval.

https://github.com/llvm/llvm-project/pull/207229