[BlackBerry] Check for a valid range object before using it
https://bugs.webkit.org/show_bug.cgi?id=109058

Reviewed by Rob Buis.

PR291394
Crash occurs if makeRange returns null, since we are using this value without checking
its validity. We had an assert before which I'm replacing with just a check for null.

Internally reviewed by Mike Fenton.

* WebKitSupport/SpellingHandler.cpp:
(BlackBerry::WebKit::SpellingHandler::getRangeForSpellCheckWithFineGranularity):


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@142006 268f45cc-cd09-0410-ab3c-d52691b4dbfc