The spec specifies that search and standard can not be valid values
for the collation extension keyword. Instead users are expected to use
the options bag to set the correct usage options.

But, ICU expects the usage option to be set through the collation
extension value.

In this patch, we set the usage option using the collation extension
value in ICU. For resolvedOptions, we filter out this extension value
using ICU to be spec compatible.

Previously, we stored the usage option on the JSCollator instance. But
this patch changes the logic to just look it up from the icu::Collator
when required. This saves one word of memory.

This fails a test262 that was incorrectly fixed. A follow on patch
will fix the test262 test.

Bug: v8:5751
Cq-Include-Trybots: luci.v8.try:v8_linux_noi18n_rel_ng
Change-Id: I8c66c6286287e686f4cd152fa1301f9d51c38654
Reviewed-on: https://chromium-review.googlesource.com/1180488Reviewed-by: Adam Klein <adamk@chromium.org>
Commit-Queue: Sathya Gunasekaran <gsathya@chromium.org>
Cr-Commit-Position: refs/heads/master@{#55437}