[ Merge from http://go/wvgerrit/151349 ]
- move plugin and mCdm creation in SetUp() test fixture
- replace StrictMock<MockCD<> with NiceMock; otherwise,
"uninteresting mock for isOpenSession" will return fail by default
- replace .WillOnce() for isOpenSession() with .WillRepeatedly
Test: m libwvdrmmediacrypto_hal_test -j128
Test: m libwvdrmmediacrypto_hal_test WV_UNITTESTS_BUILD_TARGET=hidl -j128
Test: adb push $(OUT)/data/nativetest/libwvdrmmediacrypto_hal_test /data/nativetest/.
Test: adb shell LD_LIBRARY_PATH=/vendor/lib64
/data/nativetest/libwvdrmmediacrypto_hal_test
Bug: 217247987
Change-Id: I8d7189473d52738645c73c6665f4f3f6a13042f0