Normalize testcase format

This commit normalizes the test case format used across test262. It applies the following transformations:

* Convert to YAML for frontmatter
* Remove of trailing whitespace
* Replace /r/n with /n except in chapters 6 and 7.
* Copyright header always uses // comments
* new includes attribute replaces $INCLUDE
* No implicit assumptions about test environment other than $ERROR. Everything else appears in the include array. This includes "runTestCase" which is now included in a substantial number of tests.