[RTT2] Move native initialization to local thread

Native initialization can block for a "long" period of time. It
therefore should not run on the main thread of the system service (which
will delay system startup). CL moves it off to the local thread of the
RTT service.

Bug: 68661723
Test: unit test & integration tests
Change-Id: I6e51ca080c362eec48f7810b2e013d9106376368
3 files changed