cq_test: allow test cases to be run out of order

check that bitrates increase with cqlevel at global test case teardown,
rather than after each individual test case. this allows the tests to be
run out of order with --gtest_shuffle.

Change-Id: I9e0d4e6a2d920a1f2fe9aee7b7876a3e7eb5d297
1 file changed