[PM] As Dave noticed in review, I had erroneously copied the move
constructors from the classes which only have a single reference member
to many other places. This resulted in them copying their single member
instead of moving. =/ Fix this.

There's really not a useful test to add sadly because these move
constructors are only called when something deep inside some standard
library implementation *needs* to move them. Many of the types aren't
even user-impacting types. Or, the objects are copyable anyways and so
the result was merely a performance problem rather than a correctness
problem.

Anyways, thanks for the review. And this is a great example of why
I wish I colud have the compiler write these for me.