Fix String Change baseline compiler errors.

The String Change adds multiple move results if the uninitialized string
is in multiple registers. This adds StoreLocals on the same instruction,
which isn't allowed. Now, a LoadLocal is added for each extra move
needed.

bug:21902634

(cherry picked from commit aa919207d2fb63af11d72d3b7cdbc435769565af)

Change-Id: I057d14cdac437d06eec20caaddd430c304e58196
1 file changed