OobPairingSl4aTest: New suite of pairing tests for OOB.

SL4A + GD Cert test to test OOB pairing cases for Android.

- Generate local oob data for BLE transport.
- Generate Classic OOB Data.
- Generate OOB data twice consecutively (This test waits for the callback in between calls.)

Bug: 201087902
Test: gd/cert/run --clean --device --sl4a OobPairingSl4aTest
Tag: #stability
Change-Id: Ia93b93667a871893ce27a5fb413aaa7aa702895a