[clang] [AST][NFC] Rename checkFloatingPointResult to PointResultForOpportunisticFolding. (PR #213750)

[Hubert Tong via cfe-commits]

hubert-reinterpretcast wrote:

> "opportunistic constant folding" is not a term we ever use. I don't even know what that's supposed to be.

Would dropping the "opportunistic" help? I think "constant folding" would convey the idea.

https://github.com/llvm/llvm-project/pull/213750