Allow for setting test type as a monkey.

1. This allows UiAutomation type tests to run as if an
   android monkey test is running. This allows applications
   that recognize that they are drive by a test framework and
   avoid performing certain actions such as calling 911.

2. Fixed a bug where the UiAutomation#disconnect() was not
   called when the instrumentation is shutdown.

bug: 8588857

Change-Id: I9e3624dfbe2b8f81f27805711de1098ea2edd03d