{PrintCollection} can print any collection which is iterable via a
standard for-each loop in C++. The output format of {4, 7, 11} is:
[4, 7, 11]

This helper avoids a few repetitions of manually outputting such
collections.

R=titzer@chromium.org

Bug: v8:7754
Cq-Include-Trybots: luci.v8.try:v8_linux_noi18n_rel_ng
Change-Id: Iaa91e5465968a029815b3aa2b35948f711956cdb
Reviewed-on: https://chromium-review.googlesource.com/1112005
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#54048}