Add scan result logs.

Some GMSCore modules are missing some scan result despite the peer
device is discovered by the Android BT stack. These logs will help debug
such problems.

Bug: 154942993
Bug: 199827901
Test: IOP and BCST
Tag: #stability

Change-Id: I6bd98df09ea2beb695aa9b4ac63bde307e77b182
(cherry picked from commit f204effb5cc6f1cc8e5e3f75ef343db3bd339b67)