cheets_CTS_R: Update bisector default version to 'LATEST'.

BUG=b:176141402
TEST=none

Change-Id: I297d78855c6b5b887200bef1238e96ade147abbe
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/autotest/+/2599680
Reviewed-by: Kazuhiro Inaba <kinaba@chromium.org>
Reviewed-by: Jiyoun Ha <jiyounha@chromium.org>
Reviewed-by: Kuang-che Wu <kcwu@chromium.org>
Tested-by: Kazuhiro Inaba <kinaba@chromium.org>
Commit-Queue: Kazuhiro Inaba <kinaba@chromium.org>
Auto-Submit: Kazuhiro Inaba <kinaba@chromium.org>
diff --git a/server/site_tests/cheets_CTS_R/control.tradefed-run-test b/server/site_tests/cheets_CTS_R/control.tradefed-run-test
index 617cce9..31f1556 100644
--- a/server/site_tests/cheets_CTS_R/control.tradefed-run-test
+++ b/server/site_tests/cheets_CTS_R/control.tradefed-run-test
@@ -31,7 +31,7 @@
 cts_abi = 'arm'
 cts_module = ''
 cts_retry = 5
-cts_revision = '6896666'  # TODO(kinaba): Set this default value from generator.
+cts_revision = None
 cts_test = ''
 cts_timeout = 600
 
@@ -61,7 +61,7 @@
 
 # And we are getting ready for tradefed.
 uri = ('gs://chromeos-arc-images/cts/bundle/R/android-cts-' + cts_revision +
-       '-linux_x86-' + cts_abi + '.zip') if cts_revision else None
+       '-linux_x86-' + cts_abi + '.zip') if cts_revision else 'LATEST'
 run_template = ['run', 'commandAndExit', 'cts',
                 '--include-filter', cts_module + ' ' + cts_test,
                 '--logcat-on-failure']