.. otherwise V8 crashes on attempt to use imported function as part
of expression passed to Debugger.evaluateOnCallFrame.

R=neis@chromium.org

Bug: chromium:878029
Cq-Include-Trybots: luci.chromium.try:linux_chromium_headless_rel;master.tryserver.blink:linux_trusty_blink_rel
Change-Id: I61b837f5c7b84a80d91a9cdaaac0422a24aa1620
Reviewed-on: https://chromium-review.googlesource.com/1241475Reviewed-by: Georg Neis <neis@chromium.org>
Commit-Queue: Aleksey Kozyatinskiy <kozyatinskiy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#56216}