The implementation of cache/restore of RegExp properties
has the potential to cause a number of issues.  A perfect
solution is not possible because it's not possible to
determine the regex that was used to turn the cached input
into the cached match and group matches.  The current
solution simply takes the lastMatch and escapes it,
wrapping any match groups in parens.  One problem with
this approach is that when the match is very long, it
will overrun the maximum length of a RegEx in JavaScript.

In this commit, we add the capability to disable restore
of RegExp properties entirely, via
`IntlPolyfill.__disableRegExpRestore`.

Previously createRegExpRestore build a regex with the exact characters for each part of the expression (either capturing group, or segment between capturing groups).  The new solution begins with this approach, and then shortens the resulting expression by replacing each segment with a match for character count only, then setting lastIndex on the resultant RegExp to ensure that the match occurs at the expected location in the input.

createRegExpRestore now returns a restore function rather than an
object that must be operated on.  This commit updates the usage
of this function to line up with the new implementation