Update PropertySourcesPropertyValues so that source detection logic for
collection values also considers complex types. Prior to this commit
properties of the following form were processed correctly:

	PropertySource-A
	  list[0]=x

	PropertySource-B
	  list[0]=y
	  list[1]=z

But properties of the form were not:

	PropertySource-A
	  list[0].name=x

	PropertySource-B
	  list[0].name=y
	  list[1].name=z

Fixes gh-4313
See gh-2611