Implements ES6 String.prototype.normalize method.

BUG=v8:2943
LOG=Y
TEST=Unit tests for "real life" use cases, edge cases, various types of normalization.

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This is identical to the previous CL
   https://codereview.chromium.org/40133004/
with two differences:
 * Added a dummy implementation of String.prototype.normalize to be used when v8 is compiled without intl support
 * Rebased the the test files for webkit. That was the only reason for the previous failure (and revert).

Thank you,
Mihai

R=svenpanne@chromium.org

Review URL: https://codereview.chromium.org/68133016

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@18972 ce2b1a6d-e550-0410-aec6-3dcde31c8c00