eclass/cros-rust: Properly set default host tests.

Some tests are building for the host. This change sets
CROS_RUST_HOST_TESTS to include them by default.

BUG=chromium:1154084
TEST=CQ passes

Change-Id: I0ea57397c6538530adec9dcbff6b2c0be50240f8
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/overlays/chromiumos-overlay/+/2586658
Tested-by: Allen Webb <allenwebb@google.com>
Commit-Queue: Allen Webb <allenwebb@google.com>
Reviewed-by: Chirantan Ekbote <chirantan@chromium.org>
5 files changed