Previously in the JS implementation, this would throw (on property
access) but this new behavior is more in line with how all the other
intl objects work.

Bug: v8:5751, chromium:880697
Cq-Include-Trybots: luci.v8.try:v8_linux_noi18n_rel_ng
Change-Id: I0bd073b2a0a6fc1eacd686083d8f1a72252cea53
Reviewed-on: https://chromium-review.googlesource.com/1207579
Commit-Queue: Sathya Gunasekaran <gsathya@chromium.org>
Reviewed-by: Adam Klein <adamk@chromium.org>
Cr-Commit-Position: refs/heads/master@{#55664}