GWP-ASan: Report allocator region bounds

Recently while looking at crashes I have wished that I knew whether the
allocation I was looking at was the first/last allocation in the region.
Send the allocator bounds along in crash reports.

Bug: 896019
Change-Id: I1cfad6020f7a61292ba1c3faccf0700bcc425ab4
Reviewed-on: https://chromium-review.googlesource.com/c/1406294
Commit-Queue: Vlad Tsyrklevich <vtsyrklevich@chromium.org>
Reviewed-by: Vitaly Buka <vitalybuka@chromium.org>
Cr-Commit-Position: refs/heads/master@{#622333}
3 files changed