Add fast/encoding layout tests.

Merged from WebKit at r67178.

The vast majority of these are passing. The exceptions:
- Three Mac-specific tests, won't fix.
- Four failures in the Java HTTP stack (no problem for the Chrome HTTP stack).
- fast/encoding/mailto-always-utf-8 needs a new LayoutTestController callback.

Change-Id: I16c613d42acd0ea2dc146909d514376d0a2e5aaa
193 files changed