Expand consistency testing with i-mean sponges

  Use tmp_scale when taking the i-mean interface heights for i-mean sponges, to
give a greatly expanded range of dimensional consistency testing.  All answers
are bitwise identical.

src/parameterizations/vertical/MOM_sponge.F90

@@ -420,7 +420,7 @@ subroutine apply_sponge(h, dt, G, GV, US, ea, eb, CS, Rcv_ml)
         eta_anom(i,j) = e_D(i,j,k) - CS%Ref_eta_im(j,k)
         if (CS%Ref_eta_im(j,K) < -G%bathyT(i,j)) eta_anom(i,j) = 0.0
       enddo ; enddo
-      call global_i_mean(eta_anom(:,:), eta_mean_anom(:,K), G)
+      call global_i_mean(eta_anom(:,:), eta_mean_anom(:,K), G, tmp_scale=US%Z_to_m)
     enddo
 
     if (CS%fldno > 0) allocate(fld_mean_anom(G%isd:G%ied,nz,CS%fldno))