Remove un-necessary post

Airplane and satellite handler are running on the correct looper. post
is not necessary
For userSwitch posting delayed with a 0 delay isn't giving value.

finally, remove the synchronized in the airplane handler as this is not
called by multiples thread

Bug: 328842491
Flag: Exempt, no-op
Test: atest ServiceBluetoothTests
Change-Id: I4d2e8d7bf6e25ca36157aa2d9ac9dc4ee8fd36f0