Merge Parser::ReportUnexpectedToken and PreParser::ReportUnexpectedToken.

(I.e., move ReportUnexpectedToken to ParserBase.)

Because of the recent unifications, they now do the same thing.

BUG=
R=mstarzinger@chromium.org

Review URL: https://codereview.chromium.org/153743006

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@19161 ce2b1a6d-e550-0410-aec6-3dcde31c8c00