Handle Prefetch Constraints with Flexibility Controller

Handling prefetch constraints in FlexibilityController by querying
PrefetchController's cached estimated runtime and passing a listener to
PrefetchController that notifies FlexibilityController when the cache has
been updated. Also added a reset function and abstracted out timing
functions to handle prefetch edge cases.

Bug: 238887951

Test: atest frameworks/base/services/tests/mockingservicestests/src/com/android/server/job
Test: atest frameworks/base/services/tests/servicestests/src/com/android/server/job
Test: atest CtsJobSchedulerTestCases
Change-Id: I0186434c3396cd7a721008168cb8d33b830d6d5a