Speeding up inspector/jump-to-previous-editing-location.html test

This patch speeds up inspector/jump-to-previous-editing-location.html
with the following tricks:
- eventSender usage was eliminated. The only exception is first test
from testsuite that was left as-is to verify top-down behaviour.
- the whole InspectorView was removed from rendering tree to speedup all the following
testcases

BUG=336481

Review URL: https://codereview.chromium.org/143523012

git-svn-id: svn://svn.chromium.org/blink/trunk@165638 bbb929c8-8fbe-4397-9dbb-9b2b20218538