message: add fast path to Pointer::blockValRefined
  if memories compare syntactically dont bother comparing each byte
diff: @@ -792,6 +792,9 @@ expr Pointer::fninputRefined(const Pointer &other, bool is_byval_arg) const {
  }
  expr Pointer::blockValRefined(const Pointer &other) const {
  + if (m.non_local_block_val.eq(other.m.non_local_block_val))
  + return true;
  +
  Byte val(m, m.non_local_block_val.load(shortPtr()));
  Byte val2(other.m, other.m.non_local_block_val.load(other.shortPtr()));
  