Refactor access to psi elements when not needed (follow-up #2901)

[paul-dingemans]

Got it. If this is non-essential, can we save it for another PR? This one is feeling too large already.

Originally posted by @mgroth0 in #2901 (comment)

Code blocks like below:

                ?.psi
                ?.safeAs<KtFunctionLiteral>()
                ?.bodyExpression
                ?.node

convert an ASTNode to an PsiElement and use Psi constructs. Those constructs can be rewritten to use less Psi functionality and as of that improve performance by reducing the chance of Psi cancellation checking.