Improve the net-capabilities scheme for backward compatibility

- Create a new XML tag for the new format. The new format should
  persist the arrays of values without assuming they necessarily
  have different bits.

- Upon reading, if the new tag is present, use that. If the new
  tag is not present but the old tag is present, then limit the
  contents to the capabilities/transports that existed in R.

- Catch all exceptions and ignore the requests if they can't be
  re-read from disk. This is a measure to avoid any mistake where
  the device couldn't boot when JS tries to restore state.

Bug: 183071974
Test: atest JobStoreTest
Original-Change: https://android-review.googlesource.com/1679762
Merged-In: I56cde50d2adab81134c8be4f6996d68018f4212a
Change-Id: I56cde50d2adab81134c8be4f6996d68018f4212a