Fix a bug in the insertion of parallel move.

To make sure we do not connect interval siblings in the
same parallel move, I added a new field in MoveOperands
that tells for which instruction this move is for.
A parallel move should not contains moves for the same instructions.

The checks revealed a bug when connecting siblings, where
we would choose the wrong parallel move.

Change-Id: I70f27ec120886745c187071453c78da4c47c1dd2