Clean up v8_interface.generate_overloads_by_type

(Preliminary refactoring for overload resolution.)

This fixes generate_overloads_by_type to progressively filter lists,
and then apply a short piece of code to them,
instead of having lots of redundant checks and long loops.
(removes 4 |continue| statements by making lists explicit)

R=haraken
BUG=293561

Review URL: https://codereview.chromium.org/238593002

git-svn-id: svn://svn.chromium.org/blink/trunk@171531 bbb929c8-8fbe-4397-9dbb-9b2b20218538