Handlify concat string and substring.

R=ulan@chromium.org
BUG=

Review URL: https://codereview.chromium.org/50073005

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@17490 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Add simple inline macros to js2c and use that for typed array constructors.

R=yangguo@chromium.org

Review URL: https://codereview.chromium.org/44173003

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@17491 ce2b1a6d-e550-0410-aec6-3dcde31c8c00