Merge NetdServiceMonitor into NetdMonitor.

- This is a no-op refactor for reducing duplicated code.
- Add a global NetdMonitor which can use for every test.
- Statically import INetd permissions.

Bug: 189705071
Test: atests FrameworksNetTests
Change-Id: I78f4b46cce16ea7e25b67cf2e9470cb09f1c3e75
2 files changed