merge immutable-arraybuffer tests

[phoddie]

Suite of test262 tests for the Immutable ArrayBuffer proposal.

[gibson042]

@phoddie This is pretty noisy right now; please fix the lint issues:

• Add necessary front matter fields
• Update features.txt
• Fix the copyrights to a single year rather than a range
• etc.

[phoddie]

Sure, will do. FWIW – "Fix the copyrights to a single year rather than a range" feels artificial.

[ljharb]

It's not; it ensures that the range doesn't need to be updated every year.

[gibson042]

Rebasing on main will also get the annotation improvements from #4449.

[phoddie]

It's not; it ensures that the range doesn't need to be updated every year

??? The range only needs to be updated in years when the tests are modified, not when the calendar advances. Anyway. I will change the tests to conform with this peculiar requirement.

[phoddie]

The linter is now happy and I've attempted to resolve all comments.

[gibson042]

I am a champion of the proposal and will not formally approve this PR would appreciate attention from other maintainers, but I have reviewed it and confirmed consistency with the proposal. Followups are expected to cover error handling and ArrayBuffer.prototype.sliceToImmutable, but this LGTM.

[gibson042]

Nit:

Suggested change

	var immutable = Object.getOwnPropertyDescriptor(
	ArrayBuffer.prototype, "immutable"
	);
	var getter = immutable.get;
	var getter = Object.getOwnPropertyDescriptor(
	ArrayBuffer.prototype, "immutable"
	).get;

[gibson042]

Nit:

Suggested change

	var immutable = Object.getOwnPropertyDescriptor(
	ArrayBuffer.prototype, "immutable"
	);
	var getter = immutable.get;
	var getter = Object.getOwnPropertyDescriptor(
	ArrayBuffer.prototype, "immutable"
	).get;