Use deep copy when copying bpPropertySets

Previously, only a shallow copy was made so the copy ends up sharing
some contents with the original. That was a potential source of bugs
as the copy was being made in order to be mutated.

This change switches to a deep copy; renaming the methods from
copy -> deepCopy to clarify the intent.

Makes the bpPropertySet member of bpModule a *bpPropertySet to avoid
unnecessary copying of bpPropertySet.

Bug: 142940300
Test: m nothing
Change-Id: I3f2eaa9fffab4e61d5a7cec81aa42fee9fdfec44