Add ".copy" before extension when copying a Swift object.

When the object has no extension the string is appended to the end:
test.pdf => test.copy.pdf
test => test.copy

Change-Id: I50077f6c7a7295ebb7caf7500a5738a856e6a435
Closes-Bug: #1231544
Merge "Add ".copy" before extension when copying a Swift object."