Update RegExp tests for CharacterClassEscape \S

Intl.Locale: Update expectation for empty values for collation and numberingSystem.

The spec changed in https://github.com/tc39/proposal-intl-locale/pull/47.

The tests for calendar were already correct.

Update tests for String.prototype.matchAll

Update RegExp Unicode property escape tests per Unicode 11

GetTemplateObject with a unique template object

As per spec changes (https://github.com/tc39/proposal-string-matchall/pull/35), removed tests related to the removed IsRegExp call.
To prevent older implementations (not observing spec change) from passing, added a new test to verify the reduced number of observable calls to IsRegExp.

Also fix a misreference in `features` frontmatter.

intl402/NumberFormat/length.js: remove calls to verifyNotEnumerable, verifyNotWritable, verifyConfigurable. Fixes gh-1591

Add tests for Symbol.prototype.description

Reflect.ownKeys: order with large integer "index" keys

Emoji data is now published as part of the Unicode standard itself, and thus follows the same version number.

Ref. https://github.com/mathiasbynens/unicode-property-escapes-tests/commit/f302c60c846278e94bf5c5f47f5da49947940944.
Ref. https://github.com/tc39/ecma262/pull/1218.
Ref. https://github.com/tc39/ecma262/issues/1219.

Add a test for passing Intl.Locale objects to Intl.getCanonicalLocales().

Add tests for branding checks in Intl.Locale.prototype members.

Implementation Contributions: Creating initial empty dir for receiving "upstreamed" test material via automaton

Intl: Update language subtag data to "IANA language subtag registry, file date 2018-04-23"

Date.parse breathing test, time value maximum range test

Add tests for the names of getters on Intl.Locale.prototype.

Various additions to the Intl.Locale test coverage.

Add a test for Locale#{minimize,maximize}.

Add Object.prototype.toString tests for BigInt.

fix: comparing typeof expression

Reported by André Bargull in
<https://bugzilla.mozilla.org/show_bug.cgi?id=1464758>.

Add a test for pluralrules.resolvedOptions().pluralCategories.