update test framework to use Mockito 2.12

Had to change 1 line in the test because of an error
generated from changing mockito version.

Bug: 70897712
Test: run ./frameworks/opt/net/wifi/tests/wifitests/runtests.sh

Change-Id: Ie1c0788a071f465bd37f8bdccb266ddbab7a5941
3 files changed