Precision issue in Firefox/SpiderMonkey

[andyearnshaw]

=== intl402/ch11/11.3/11.3.2_TRP failed in non-strict mode ===
--- errors ---
uncaught exception: Test262 Error: Formatted value for 123.44500, aa-DJ-u-nu-latn and options {"useGrouping":false,"minimumSignificantDigits":3,"maximumSignificantDigits":5} is 123.44; expected 123.45.
===

This is both partially my fault for being lazy, and Mozilla's fault for not fixing this bug. On my side, for the abstract functions ToRawFixed and ToRawPrecision, I used Number.prototype.toFixed and Number.prototype.toPrecision to cheat. Both those functions have similar rounding bugs in v8 and in SpiderMonkey, but I thought the workaround I added fixed the issue.

The implemented workaround doesn't fix the problem in SpiderMonkey, so this test fails in that environment.