Add extra conditions to test HeaderListViewAdapter isEmpty

Fix for Issue ID 18316. Test that HeaderListViewAdapter isEmpty() returns false when HeaderListViewAdapter getCount() returns a non-zero value. So that the list cannot be considered empty when a header or footer is present.

https://code.google.com/p/android/issues/detail?id=18316



Change-Id: I2e5db20bacf9f17303adc1d433d983036a16535c
Signed-off-by: Emma Sajic <esajic@effectivelateralsolutions.co.uk>