cros_run_unit_tests: add --pretend helper

This makes it easier to debug issues.

BUG=chromium:342180
TEST=`./cros_run_unit_tests --board=sonic` tries to build things
TEST=`./cros_run_unit_tests --board=sonic --pretend` only shows packages to be tested

Change-Id: Idfe1f80f04a3b95e6eb070c53efc37df9adb3dc8
Reviewed-on: https://chromium-review.googlesource.com/185594
Reviewed-by: Gaurav Shah <gauravsh@chromium.org>
Commit-Queue: Mike Frysinger <vapier@chromium.org>
Tested-by: Mike Frysinger <vapier@chromium.org>
1 file changed