The streaming compilation cctests test streaming compilation over the
public API, as far as possible. It is not required that a HandleScope
is open when the API is used. Therefore the cctest should also not open
a global HandleScope for a whole test but as fine-grained as possible.

R=clemensh@chromium.org

Bug: v8:8055 v8:8015
Change-Id: Id5e2145f2a8ba66e8d5d9021c47806aa80fc463f
Reviewed-on: https://chromium-review.googlesource.com/1174258Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Commit-Queue: Andreas Haas <ahaas@chromium.org>
Cr-Commit-Position: refs/heads/master@{#55113}