Dropped series of load ops to same address could be reduced to single op

[MaxGraey]

Inspired by this issue

drop (i32.load $addr, offset=0)
  ...
drop (i32.load $addr, offset=8)
  ...
drop (i32.load $addr, offset=16)

Could be reduced to:

drop (i32.load $addr, offset=16) ;; leave only single `load` with highest `offset`