Re-apply: enable/disable from main thread earlier

Initial CL: 0ef8f2fa
Revert: 96f2d362

Change between initial revert and this:
* https://r.android.com/3245123 : the shutdown will more likely to be
  completed in time and snapshot will not happen in the middle
* The postAndWait timeout is now 10 seconds instead of 1. This is to
trigger an explicit ANR to be actionable.

Note that call coming from binder thread is a known source of flakiness
when stress testing the Bluetooth start / stop.

Bug: 262605980
Bug: 288450479
Test: atest ServiceBluetoothTests
Change-Id: Ib763a35979807a4804a79757d0e42714e22f6b24