fix run_remote_tests.sh control file combining logic

This CL fixes a bug in the control file combining logic which was
causing tests to be run multiple times under some circumstances. It also
improves the logging messages in the preamble to a suite run.

BUG=chromium:224679
TEST=run_remote_tests.sh --remote=172.22.75.104 suite:dummyflake; 4
tests are run instead of 8.

Change-Id: If8ccaa0a03232cfb1d341fc9fb10b87daddd74c1
Reviewed-on: https://gerrit.chromium.org/gerrit/46785
Tested-by: Aviv Keshet <akeshet@chromium.org>
Reviewed-by: Chris Sosa <sosa@chromium.org>
Commit-Queue: Aviv Keshet <akeshet@chromium.org>
1 file changed