If the regex always matches the input, even if it's past the end, then
we need to stop execution of the regex when it's past the end. This
corresponds to step 13.a and prevents it from infinitely looping.
Reduced from: d98672060f/packages/react-i18n/src/utilities/money.ts (L10-L14)
This should be using the individual flag boolean properties rather than
the [[OriginalFlags]] internal slot.
Use an enumerator macro here for brevity, this will be useful for other
things as well. :^)
- Default values should depend on arguments being undefined, not being
missing
- "(?:)" for empty pattern happens in RegExp.prototype.source, not the
constructor
This makes RegExpObject compile and store a Regex<ECMA262>, adds
all flag-related properties, and implements `RegExpPrototype.test()`
(complete with 'lastIndex' support) :^)
It should be noted that this only implements `test()' using the builtin
`exec()'.
This should not just inherit Object.prototype.toString() (and override
Object::to_string()) but be its own function, i.e.
'RegExp.prototype.toString !== Object.prototype.toString'.