Improve rejection test for character-based SVG text queries

Perform an intersection of the involved ranges to reject fragments early,
while still avoiding calls to mapStartEndPositionsIntoFragmentCoordinates.
This means the "cache" added in https://codereview.chromium.org/349223003
can be dropped, since we'll now never even reach it. This gives a moderate
speed-up - a few percent - on the original TC compared to using the cache.

BUG=267504

Review URL: https://codereview.chromium.org/359783002

git-svn-id: svn://svn.chromium.org/blink/trunk@177148 bbb929c8-8fbe-4397-9dbb-9b2b20218538