In the case of a function constructor or eval, we create a new script
object which doesn't have a script name. In this case, we traverse
upwards on the list of SFI's through script->eval_from_shared() to get
the outermost script that was not an eval script and get the script
name from that script.

Bug: chromium:746909, v8:6683, v8:5785
Change-Id: I430459f632a0e3b18fc3111a5cf1c00cedb9f520
Reviewed-on: https://chromium-review.googlesource.com/606701
Commit-Queue: Sathya Gunasekaran <gsathya@chromium.org>
Reviewed-by: Adam Klein <adamk@chromium.org>
Reviewed-by: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47352}