Fixed UiDevice.dumpWindowHierarchy(..) to work under instrumentation

Filenames are now relative to the application's private internal storage
directory. The previous location /data/local/tmp is not writable when
running under instrumentation.

Also changed the function to support absolute paths.

Bug: 10788452
Change-Id: I2b797f3f6b820354b231b03395782f3e8e776519
3 files changed