combine: More make_more_copies

combine: More make_more_copies

This makes make_more_copies do what its documentation says, that is,
only make an intermediate pseudo if copying to a pseudo.

This regressed generated code quality when we didn't keep the original
notes that were on the copy, but since r265582 we do, and only allowing
pseudos now is a win.  It also simplifies the code.

	* combine.c (make_more_copies): Only make an intermediate copy if the
	dest of a move is a pseudo.

From-SVN: r266004