IDL compiler: always use raw pointer in visitDOMWrapper

Remaining: 16 => 14

Perl code always uses a raw pointer in visitDOMWrapper,
even for non-wrapper types, notably NodeFilter.
Thus we get
NodeFilter*
instead of the usual
RefPtr<NodeFilter>

Question: Is this correct? It's weird and inconsistent.

Perhaps this is a bug in Perl, and anyway it's an inconsistency,
so I've marked it as FIXME, but this CL makes the Python match the Perl.

BUG=239771
R=haraken, kouhei
NOTRY=true

Review URL: https://codereview.chromium.org/177103002

git-svn-id: svn://svn.chromium.org/blink/trunk@167742 bbb929c8-8fbe-4397-9dbb-9b2b20218538