Support remote-android with multiple connected devices.

Summary:
This change introduces a new URL scheme for `platform connect`:
```
adb://device-id:port
```

Reviewers: vharron, tberghammer, clayborg, ovyalov

Reviewed By: ovyalov

Subscribers: tberghammer, lldb-commits

Differential Revision: http://reviews.llvm.org/D9358

llvm-svn: 236321