Fix run-bindings-tests: excess files in Python, SVG test

Follow-up to Terry's recent:
Fixed run-bindings-tests so results are tested.
https://chromiumcodereview.appspot.com/179993004/

Now assumes that the Python directory has exactly the same output,
so need to switch SVG test so it works (only one actual special case!)
and special-case the other generated file (EventInterfaces.in).
(Also I made a rebasing error, so it skipped Python.)

R=haraken@chromium.org
TBR=haraken
NOTRY=true

Review URL: https://codereview.chromium.org/180753003

git-svn-id: svn://svn.chromium.org/blink/trunk@167840 bbb929c8-8fbe-4397-9dbb-9b2b20218538