Just add tests so we can observe the number first.

Got the following results
$ python -u tools/run_perf.py --binary-override-path   out/x64.release/d8 --filter "JSTests/Intl"   test/js-perf-test/JSTests.json
INFO      >>> Running suite: JSTests/Intl
INFO      >>> Stdout (#1):
NewIntlCollator-Intl(Score): 161
NewIntlDateTimeFormat-Intl(Score): 9.73
NewIntlNumberFormat-Intl(Score): 18.6
NewIntlPluralRules-Intl(Score): 18.5
NewIntlListFormat-Intl(Score): 19.4
NewIntlRelativeTimeFormat-Intl(Score): 18.7

Bug: chromium:928098
Change-Id: I59f28393af8f868de639dcb81a7b2f69ce2f0eba
Reviewed-on: https://chromium-review.googlesource.com/c/1455717
Commit-Queue: Frank Tang <ftang@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59424}