Make TestApis static.

Currently we create a TestApis in every test class but we don't actually
make use of the state so it's wasteful and makes our APIs more complex.

This is a big change but it should have no functional change.

Test: atest NeneTest
Test: atest TestAppTest
Test: atest HarrierTest
Test: atest RemoteDpcTest
Test: atest CtsDevicePolicyTestCases
Fixes: 200779840
Change-Id: I8f839d411e1bcd1b18fdd61c650a65fc37fc47fd
122 files changed