sqlite: Disable mmap usage on Windows.

This is an experiment to see if the crashes in the referenced bug are
related to mmap changes on Windows. This CL will be reverted after it
goes live in 1-2 canaries.

TBR=cmumford

Bug: 897576
Change-Id: Ic44836c4ed848f8713d16b553f038c63119f0aaf
Reviewed-on: https://chromium-review.googlesource.com/c/1348736
Commit-Queue: Victor Costan <pwnall@chromium.org>
Reviewed-by: Victor Costan <pwnall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#610551}
2 files changed