Keep references while moving other expressions into a temp

Keep references while moving other expressions into a temp

delete and typeof need to get correct references as arguments.
But we still need to evaluate other expressions correctly. The
best way to do that is to store them in a temp.

Change-Id: I7bcd152742bf752df47fd63a837952c57ea70bf5
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>