cheets_GTS: preparer whitelist workaround for collect-tests-only.

The whitelisting has already landed (ag/3850281) to the HEAD of the
GTS release branch, but until it is pushed, we want to modify the
whitelist manually.

BUG=b:67474330
TEST=test_that cheets_GTS.tradefed-run-collect-tests-only

Change-Id: I0d63a26f681256358a95e7698aa1c81fcece8133
Reviewed-on: https://chromium-review.googlesource.com/1023493
Commit-Queue: Kazuhiro Inaba <kinaba@chromium.org>
Tested-by: Kazuhiro Inaba <kinaba@chromium.org>
Trybot-Ready: Kazuhiro Inaba <kinaba@chromium.org>
Reviewed-by: Ilja H. Friedel <ihf@chromium.org>
(cherry picked from commit c16bb9d4678c1818e60c5f8b2371e76ec345dd0b)
Reviewed-on: https://chromium-review.googlesource.com/1025677
Reviewed-by: Kazuhiro Inaba <kinaba@chromium.org>
diff --git a/server/site_tests/cheets_GTS/control.tradefed-run-collect-tests-only b/server/site_tests/cheets_GTS/control.tradefed-run-collect-tests-only
index 8db9586..43fb074 100644
--- a/server/site_tests/cheets_GTS/control.tradefed-run-collect-tests-only
+++ b/server/site_tests/cheets_GTS/control.tradefed-run-collect-tests-only
@@ -20,7 +20,10 @@
         host=host,
         iterations=1,
         tag='tradefed-run-collect-tests-only',
-        tradefed_args = ['run', 'commandAndExit', 'collect-tests-only'],
+        tradefed_args = ['run', 'commandAndExit', 'collect-tests-only',
+                # TODO(kinaba): workaround until ag/3850281 is made public.
+                '--preparer-whitelist',
+                'com.android.tradefed.targetprep.suite.SuiteApkInstaller'],
         timeout=600)
 
 parallel_simple(run_GTS, machines)