Statsd test mapping

Makes a test mapping for statsd so that unit tests run on presubmit.

Changes to make the tests pass:
1. Require root. This is needed to write to disk, since the tests don't
run as statsd's uid

2. Remove AndroidTest.xml file in favor of the autogenerated one.

3. Remove a check in StatsService.test for getUidFromArgs. The test
checked a failure case where we passed a number bigger than INT32_MAX.
However, on a 32 bit device, strtol will return INT32_MAX when an
overflow happens, since it returns a 32 bit number on a 32 bit device.

4. Refactor a lot of e2e tests to sort dimensions, ensuring that the
dimensions are always in order, instead of relying on implicit ordering
of hashing, which can change.

5. Change a long to an int64 in TestActivationsPersistAcrossSystemServerRestart

Test: statsd_test
Bug: 129613474
Change-Id: I80dfa3bfd50ebe6d2c8c0c3ba201f3ad06b68910