[encoding-tests] Throw RangeErrors in TextEncoder/TextDecoder constructors. (#1761)

Fixes #5620.
Fix the TODOs and FIXMEs to comply with the spec.
Add test case for passing invalid invalid labels.
Update test metadata; three test cases have been resolved upstream and
will be fixed whenever the rust-encoding dependency is sufficiently upgraded.

View on GitHub: https://github.com/w3c/web-platform-tests/pull/1761

Received on Thursday, 16 April 2015 10:51:13 UTC