Unreviewed, rolling out r209058 and r209074.

Unreviewed, rolling out r209058 and r209074.
https://bugs.webkit.org/show_bug.cgi?id=165188

These changes caused API test StringBuilderTest.Equal to crash
and/or fail. (Requested by ryanhaddad on #webkit).

Reverted changesets:

"Streamline and speed up tokenizer and segmented string
classes"
https://bugs.webkit.org/show_bug.cgi?id=165003
http://trac.webkit.org/changeset/209058

"REGRESSION (r209058): API test StringBuilderTest.Equal
crashing"
https://bugs.webkit.org/show_bug.cgi?id=165142
http://trac.webkit.org/changeset/209074

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@209120 268f45cc-cd09-0410-ab3c-d52691b4dbfc