Create utility methods to enable and disable the bluetooth adapter for
cts tests.

Bug: 148916727
Test: atest BasicAdapterTest, atest BluetoothLeScanTest,
atest HearingAidProfileTest, atest LeL2capSocketTest

Change-Id: I11b69c4521f1eeea0c239915afad83d3742d3ea8
5 files changed