Modify $262.uncallableAndIsHTMLDDA() to an optional $262.IsHTMLDDA (whose use must be guarded by a feature of the same name), and narrowly/correctly prescribe its requirements consistent with `document.all`'s behavior in HTML. 

Fix a minor error-message typo, and include the thrown error in the TypeError-testing error message.

Add a test for GetIterator(obj, ~async~) attempting to call obj[@@asyncIterator] even if that value is an object with an [[IsHTMLDDA]] internal slot.

Add tests for the case of <iterator>.return, as used in the iteration protocol, being an object that's uncallable and compares equal to `undefined`.

* BigInt.parseInt tests

* update for PR#1208

* fix copyright notices

See relevant firefox bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1408452

The RegExp named groups specification has changed to not throw
errors in certain cases. This patch updates the test262 tests to match
the new specification, and throws in an additional test that verifies
the interaction between named group syntax and other replacement.
The tests pass on a version of V8 which implements the new semantics.

https://github.com/tc39/proposal-regexp-named-groups/commit/92ceba518c2ab0d2811c2efa8248ed1b3f8b5506

* Delete identifier-let-allowed-as-lefthandside-expression-non-strict.js

Fixes #1192

This is already covered by https://github.com/tc39/test262/blob/8422147c17aa3f4061e524a8f88c251a3b371ecf/test/language/statements/for-in/head-lhs-let.js#L27

* restore for-in test

* Add missing generators feature flags

* Generate files

* Add generators flags

* fixup! Add generators flags

* additional BigInt JSON tests

* single quotes

* BigInt stringify order of steps

* Improve tests for BigInt.prototype.valueOf

* fixup! Improve tests for BigInt.prototype.valueOf

* fixup! Improve tests for BigInt.prototype.valueOf

* fixup! Improve tests for BigInt.prototype.valueOf

* BigInt valueOf tests

* add features from typeCoercion.js

As per https://github.com/tc39/ecma402/pull/160 the formatToParts.length is set to 1.

https://github.com/tc39/ecma262/pull/988 changes the iteration protocol
such that the "next" method is only loaded from the iterator object once
during the prologue of iteration, rather than during each step.