[autotest] Add a config to skip enforcing builds arg in suite job.

This is to allow testing older builds in Moblab, especially builds with suite
control files on private repo, that were not updated to the latest format.

BUG=chromium:496782,b:28446266
TEST=unittest, local run suite

Change-Id: Ia0a653d24857f4bfc3d23830e18024771c4f55b5
Reviewed-on: https://chromium-review.googlesource.com/341730
Commit-Ready: Dan Shi <dshi@google.com>
Tested-by: Dan Shi <dshi@google.com>
Reviewed-by: John Carey <ranix@google.com>
diff --git a/global_config.ini b/global_config.ini
index 2dc99dc..a0ff00d 100644
--- a/global_config.ini
+++ b/global_config.ini
@@ -87,6 +87,8 @@
 # Set to True to allow servod to be started automatically in Moblab.
 auto_start_servod: False
 
+support_builds_arg_in_suite_job: True
+
 [CLIENT]
 drop_caches: False
 drop_caches_between_iterations: False