cros_run_bvt: Support group:mainline.

In the new definition, a test is mainline if it has group:mainline
attribute. For transition, we still treat tests without any group:*
attributes as mainline too.

BUG=chromium:1005041
TEST=None

Change-Id: I100cb8697c1197b0fd70414580a3f11a9ddba87c
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crostestutils/+/1808995
Commit-Queue: Shuhei Takahashi <nya@chromium.org>
Tested-by: Shuhei Takahashi <nya@chromium.org>
Reviewed-by: Achuith Bhandarkar <achuith@chromium.org>
diff --git a/cros_run_bvt b/cros_run_bvt
index 0da0d4b..73107e1 100755
--- a/cros_run_bvt
+++ b/cros_run_bvt
@@ -103,7 +103,8 @@
 # Run mostly the same Tast tests as the bvt-tast-cq suite regardless of flags.
 # Exclude "meta" tests, as they're just designed to exercise Tast itself.
 $DEBUG tast -verbose run -build=false "$DUT" \
-  '(!disabled && !"group:*" && !informational && !"name:meta.*")'
+  '(!disabled && ("group:mainline" || !"group:*") && !informational &&
+    !"name:meta.*")'
 TAST_STATUS=$?
 
 if [ ${AUTOTEST_STATUS} -ne 0 ] || [ ${TAST_STATUS} -ne 0 ]; then