Remove unnecessary include

Between 6eeb95f0 and
7b1c2a0f, builtins.h contained
additional prototypes that have now been moved elsewhere, so we don't
need to include nodes/parsenodes.h anymore.

Fix some files that were relying on builtins.h implicitly pulling in
some unrelated stuff they needed.

Reviewed-by: Pavel Stehule <pavel.stehule@gmail.com>