Tests for NumericSeparatorLiteral. Closes gh-1051

Remove remaining cases for ...{

features: generator => generators. Fixes gh-1181

Removes previously missed object rest `...{` cases.

remove garbage: these try/catch tests don't actually test the section cited (or anything for that matter)

Cited: https://www.ecma-international.org/ecma-262/5.1/index.html#sec-12.14.1

Present: https://tc39.github.io/ecma262/#sec-strict-mode-of-ecmascript

> It is a SyntaxError if a CatchParameter occurs within strict mode code and BoundNames of CatchParameter contains either eval or arguments (13.15.1).

Promise.prototype.finally: add tests

Proxy ownKeys should throw a TypeError if returned keys are not String or Symbol. Fixes gh-1169 (#1173)

Proxy, [[OwnPropertyKeys]]: If trapResult contains any duplicate entries, throw a TypeError

See https://github.com/tc39/ecma262/pull/858.

Ref: https://github.com/tc39/ecma262/pull/833

Remove selection of incorrect async iteration tests. Fixes gh-1154