Unreviewed, rolling out r240896.

Unreviewed, rolling out r240896.
https://bugs.webkit.org/show_bug.cgi?id=194202

"Fixes leaks, but is probably not the correct fix." (Requested
by ddkilzer on #webkit).

Reverted changeset:

"Leak of WTF::StringImpl under SymbolImpl::createNullSymbol()
(48 bytes) in com.apple.WebKit.WebContent running layout
tests"
https://bugs.webkit.org/show_bug.cgi?id=193291
https://trac.webkit.org/changeset/240896

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@240903 268f45cc-cd09-0410-ab3c-d52691b4dbfc