Previous CL ag/19516273 added tests for the new logic in
ime_processing.js, which extracts properties from WM & SF trace
entries and combines them into IME trace entries. However, the
checks used in the tests were a bit vague as they just expected some
fields to be defined (non-null). This CL improves on this by specifying
some values to verify the extracted WM / SF fields' correctness.
Bug: 237744706
Test: yarn run test
Change-Id: I1f237135520f0ef5dc85b257f6602196aa534197
f6593124e5