No need to create sub strings for lazy compiles. The scanner will start from the start position provided.

Moved the creating of character streams into the scanner where possible. This uses a input buffer in the scanner class instead of a stack allocated one.

Added a UTF16 buffer for reading external ascii strings (by templating the external two byte string one) as all the source for the builtins are exposed as external ascii strings.
Review URL: http://codereview.chromium.org/661367

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@4007 ce2b1a6d-e550-0410-aec6-3dcde31c8c00