PR44684: Look through parens and similar constructs when determining

whether a call is to a builtin.

We already had a general mechanism to do this but for some reason
weren't using it. In passing, check for the other unary operators that
can intervene in a reasonably-direct function call (we already handled
'&' but missed '*' and '+').

This reverts commit aaae6b1b,
reinstating af80b8cc, with a fix to
clang-tidy.