Make stack tracing more robust
https://bugs.webkit.org/show_bug.cgi?id=115272

Reviewed by Geoffrey Garen.

CallFrame already handles stack walking confusion robustly,
so we should make sure that the actual walk handles that as well.

* interpreter/Interpreter.cpp:
(JSC::getCallerInfo):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@149205 268f45cc-cd09-0410-ab3c-d52691b4dbfc