Adding more coverage for 10.4.3 based on feedback in bug https://bugs.ecmascript.org/show_bug.cgi?id=333

Adding more tests to cover undefined being non-writable (see https://bugs.ecmascript.org/show_bug.cgi?id=223 )

Removing RegEx test-case related to https://bugs.ecmascript.org/show_bug.cgi?id=326 until open issue is resolved.

salvaged (e.g., need locale info to properly predict whether we're subject to
DST).

need to move some tests over to best practices.

All Microsoft-contributed *.js and *.py sources now have Ecma's copyright header.

https://bugs.ecmascript.org/show_bug.cgi?id=266 and https://bugs.ecmascript.org/show_bug.cgi?id=270 resolved.

Fixed.

Re-gen'ed the website.

- https://bugs.ecmascript.org/show_bug.cgi?id=44
- https://bugs.ecmascript.org/show_bug.cgi?id=45

Added support to create testcases_bestPractice.html without also adding them to default.html.

Preliminary support for tests under test/suite/internationalization has been added.

architectures), but worth keeping around for the coverage it provides.
Documented that this is expected to fail on ARM.

S7.8.5_A3.1_T7 through S7.8.5_A3.1_T9 were invalid as written.  The only way to specify unicode flags
to literal regexp patterns is through eval and similar mechanisms (e.g., Function constructor).  Fixed.

All but two of the remaining disabled tests in excludelist.xml were disabled because the tests polluted
the global JS environment, not because the tests themselves were invalid.  This is no longer an issue as
of the latest test262 harness (actually it wasn't an issue about a year ago either).  Re-enabled.

Also, two of this weren't actually this-related.  Fixed their separate issues.