The prior version of this test asserted only the property's
configurability. It was also limited to the RegExp object as returned
from the RegExp constructor.
Extend the test to verify all values of the property descriptor.
Duplicate these assertions in a separate file dedicated to the RegExp
object as created from a RegExp literal.
The specification contains an explicit informative NOTE explaining that
the 'm' flag does not effect the behavior of the '^' assertion. Add a
test to verify this.
ES2015 reads:
> RegExpUnicodeEscapeSequence :: u{ HexDigits }
>
> - It is a Syntax Error if the MV of HexDigits > 1114111.
Use the MV 0x110000 to assert the lower boundary of values which are
expected to produce the SyntaxError.
