[sql] Enable HAVE_USLEEP for more platforms.

HAVE_USLEEP affects SQLite's sleep implementation, which is used when
SQLite waits for a lock to clear.  Browser databases are generally
uncontended, but this case could happen for WebDatabase in the renderer.

BUG=none

Review URL: https://codereview.chromium.org/827523004

Cr-Commit-Position: refs/heads/master@{#312460}
3 files changed