parser-shell will help to see how much PreParsing gets slower when PreParser
starts doing more checks (especially tracking variables and scopes). It will
also show how much having preparse data (or cached data) speeds up the parsing.

R=ulan@chromium.org
BUG=

Review URL: https://codereview.chromium.org/209353008

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@20201 ce2b1a6d-e550-0410-aec6-3dcde31c8c00