Run GVN earlier.

Rationale:
Running GVN earlier allows for better subsequent
instruction simplifation. For example, running GVN
before select generation also finds the MIN in:
   if (x > a[i])
     x = a[i];

Bug: b/74026074

Test: test-art-host,target

Change-Id: I633046375637c7809a3603fdf7c5cf77e8f21167