…eExit and WTF::makeVisitor (llvm#161926)

Lambda passed to WTF::ScopeExit / WTF::makeScopeExit and
WTF::makeVisitor should be ignored by the lambda captures checker so
long as its resulting object doesn't escape the current scope.

Unfortunately, recognizing this pattern generally is too hard to do so
directly hard-code these two function names to the checker.

(cherry picked from commit c07d305)

…ine body (llvm#165650)

Fix the assertion failure in TrivialFunctionAnalysis::isTrivialImpl with
a coroutine body by caching the result with WithCachedResult.

(cherry picked from commit 2d51705)