Bitfield tests were passing or failing intermittently under VS2015 because of uninitialized variables in the test code. VS2017 was failing consistently, as was PS4.
Fixed bitfield tests by supplying partial specializations of helper functions for bool/bitfield properties.
Also added a test for copying between two bitfields.
#jira UE-58884 - //UE4/Main - Run Automated Tests Cooked PS4 - ' Error: InTestValue == NewValue BitfieldProperty2: The two values are not equal.
#rb Graeme.Thornton
#lockdown Nick.Penwarden
[CL 4064271 by Thomas Sarkanen in Main branch]