Fix test rule to dump accessibility data in timely manner

In order to dump accessibility data before service disabled and activity
closed, dumper rule must be placed in a inner rule.

- Move activity test rule to outer rule
- Wrapping stub a11y service en/disabling into a test rule
- Fix dumper that need flag to dump window/service info and nodetree
- The dumper now extends TestWatcher to gain more extension points

Bug: 114238915
Test: atest CtsAccessibilityTestCases CtsAccessibilityServiceTestCases

Change-Id: I1f3313fc4a823b34bc02c7898085dbca064050fe