Fix find_controller_test.
Fix find_controller_test.

Currently, this test both spams the console with error messages, and passes even
if the assertions are incorrect. (The test fails to fail if the FindController
breaks.)
The test uses both chai assertions and Promises incorrectly.
This CL fixes the chai assertions to use assert.strictEqual() and
assert.lengthOf(), and fixes the Promises in the test so that the test fails
when the FindController breaks.

Review-Url: https://codereview.chromium.org/2716653004

benschmaus/catapult,catapult-project/catapult,sahiljain/catapult,sahiljain/catapult,catapult-project/catapult,catapult-project/catapult-csm,benschmaus/catapult,sahiljain/catapult,benschmaus/catapult,sahiljain/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult-csm,catapult-project/catapult,benschmaus/catapult,benschmaus/catapult,catapult-project/catapult-csm,catapult-project/catapult-csm,catapult-project/catapult,catapult-project/catapult-csm,catapult-project/catapult,sahiljain/catapult,catapult-project/catapult-csm,sahiljain/catapult,benschmaus/catapult,catapult-project/catapult-csm,benschmaus/catapult