Handle array segment not defined in DataCompare

[HeidiBickner]

Added section to evaluate if array segment is not defined. If not defined in both arrays then the function returns true, otherwise returns false for the segment.

[marcesher]

@HeidiBickner Thank you! Have you confirmed that all existing unit tests pass as a result of this change, and that the Eclipse plugin functions as expected for tests where expected array values do not match actual results?