Quick: Fix wide Phi detection in GVN, clean up INVOKEs.

The detection of a wide Phi has been incorrectly looking at
the current LVN's wide sreg value map but we only intersect
live values and thus very often lose the information. This
results in failure to identify identical values, i.e.
potential missed optimizations. It also caused the bloating
of the global value map with values we would not use.

Rewrite the wide Phi detection to use the first merged LVN's
notion of wide sreg. For this to work we also need to use
the method's shorty to mark wide arguments.

Also clean up INVOKEs' processing to avoid another source
of bloating the global value map.

Bug: 16398693
Change-Id: I76718af7d62a8c6883ef43e4f47058f7eaf479e1