Fix TaskSnapshot tests when low res is disabled

Add mocks so all tests run with high-res = 0.8f and low-res = 0.5f.
Additionally, add test for when high-res = 0.8f and low-res = 0f

Test: TaskSnapshotPersisterLoaderTest
Test: TaskSnapshotCacheTest
Test: TaskSnapshotLowResDisabledTest
Bug: 149861068
Change-Id: I7a3792ae85b79e6d3a8a4e6dbf6f5ab8106bb044
4 files changed