The new compilation API (ScriptCompiler::Compile) can produce the same data, so
the separate precompilation phase is not needed. ScriptData is replaced by
ScriptCompiler::CachedData.

R=svenpanne@chromium.org
BUG=

Review URL: https://codereview.chromium.org/225753004

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@20683 ce2b1a6d-e550-0410-aec6-3dcde31c8c00