rust: reenable sanitizers for armv7

https://github.com/rust-lang/rust/commit/16c1d0ae0656a5aa929fb0a9ab5c0c740c950ded
refactored how sanitizer support is specified upstream, which wasn't
accounted for in a previous Rust roll.

BUG=b:205180351
TEST=setup_board --board=trogdor --profile=asan && ./build_packages
--board=trogdor

Change-Id: Ice9a7171b5740d2ce17958fca800c5c625c4adf0
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/overlays/chromiumos-overlay/+/3367028
Tested-by: George Burgess <gbiv@chromium.org>
Reviewed-by: Michael Benfield <mbenfield@google.com>
4 files changed