Due to lazy deserialization, we need to ensure the snapshot blob is
not freed until the Isolate is destroyed.

Re-enable a few tests that can handle lazy deserialization just fine.

Unfortunately we can't do this for all tests as UNINITIALIZED_TEST does
not sufficiently set up the isolate for lazy deserialization (there's no
Isolate::snapshot_blob_).

Bug: v8:6624
Change-Id: Icf0d217da3a4c5ff1506facc7869d2dd1ac3a983
Reviewed-on: https://chromium-review.googlesource.com/756694Reviewed-by: Yang Guo <yangguo@chromium.org>
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#49170}