Fix assert triggered in fast/regex/pcre-test-4.html We were not filtering out

Fix assert triggered in fast/regex/pcre-test-4.html We were not filtering out
all the nodes that had non-ASCII characters.  That has been fixed, but because
of the protection against over-deep recursion when filtering it is wrong to
assert that all nodes were filtered.  This change therefore also makes sure we
can cope with non-filtered nodes by adding back some code removed in
https://chromiumcodereview.appspot.com/10174017/
Review URL: https://chromiumcodereview.appspot.com/10358008

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@11487 ce2b1a6d-e550-0410-aec6-3dcde31c8c00