Add some preconditions for WmPerfTests

- Add a readme file to describe how to lock CPU/GPU frequencies
  on local test.
- Ensure gesture navigation is enabled when testing.
- Full compile the test package.
- Remove all activities before testing.

Bug: 161782101
Test: atest WmPerfTests
Change-Id: Iebcfcbc07e3fe7d3b1839b8c2e04041d7338c48e