Add a test covering the behavior of SingleLineHTMLCloseComment where the LineTerminatorSequence within is either Unicode separator code point. (#1612)

Atomics: various corrections, nit-picking and BigInt variants

* Add Intl.RelativeTimeFormat feature.

* Add tests for the shape of the Intl.RelativeTimeFormat API.

* fixup! Add tests for the shape of the Intl.RelativeTimeFormat API.

In order to satisfy the project's formatting rules, license information
was inserted into a number of files where it had been mistakenly omitted
by the original contributors [1]. In many cases, the license information
did not accurately describe the contributor or the time of contribution.
Update the information according to the information provided by the
contributors at the time each file was authored:

- atomicsHelper.js - a72ee6d9
- detachArrayBuffer.js - 70c7375b
- nans.js - b17ffc02
- nativeFunctionMatcher.js - 6b7cbb50
- proxyTrapsHelper.js d530c87b
- regexpUtils.js - 44b40e08
- tcoHelper.js - 4dc81d37

[1] 4ea2931f

SuperProperty evaluation order

Atomics: moves getReport and waitUntil into atomicsHelper.js; broad updates to all Atomics.wait tests

Ref gh-1531