Restore bit repro using FMA in selected runs

This patch modifies select calculations of PR#1616 in order to preserve bit
reproducibility when FMA optimization is enabled.  We add parentheses and
reorder terms in selected expressions which either direct or suppress FMAs,
ensuring equivalence with the previous release.

We address two specific equations in the PR.  The first is associated
with vertical friction coupling coupling coefficient.  The diff is shown
below.

-  a_cpl(i,K) = Kv_tot(i,K) / (h_shear*GV%H_to_Z + I_amax*Kv_tot(i,K))
+  a_cpl(i,K) = Kv_tot(i,K) / (h_shear + I_amax*Kv_tot(i,K))

The denominator is of the form `a*b + c*d`.  A compiler may favor an FMA
of the form `a*b + (c*d)`.  However, the modified equation is of form
which favors the `a + c*d` FMA.  Each form gives different results in
the final bits.

We resolve this by expliciting wrapping the RHS in parentheses:

  a_cpl(i,K) = Kv_tot(i,K) / (h_shear + (I_amax*Kv_tot(i,K)))

Although this disables the FMA, it produces the same bit-equivalent
answer as the original expression.

----

The second equation for TKE due to kappa shear is shown below.

-  tke_src = dz_Int(K) *(((kappa(K) + kappa0)*S2(K) - kappa(k)*N2(K)) - &
-                              (TKE(k) - q0)*TKE_decay(k)) - &
+  tke_src = h_Int(K) * (dz_h_Int(K)*((kappa(K) + kappa0)*S2(K) - kappa(k)*N2(K)) - &
+                              (TKE(k) - q0)*TKE_decay(k)) - &
    ...

The outer equation was of the form `b + c` but is promoted to `a*b + c`,
transforming it to an FMA.

We resolve this by suppressing this FMA optimization:

  tke_src = h_Int(K) * ((dz_h_Int(K) * ((kappa(K) + kappa0)*S2(K) - kappa(k)*N2(K))) - &
                         (TKE(k) - q0)*TKE_decay(k)) - &
        ...

----

The following two changes are intended to be the smallest modification
which preserves answers for known testing on target compilers.  It does
not encompass all equation changes in this PR.  If needed, we could
extend these changes to similar modifications of PR#1616.

We do not expect to support bit reproducibility when FMAs are enabled.
But this is an ongoing conversation, and the rules around FMAs should be
expected to change as we learn more and agree on rules of
reproducibility.

src/parameterizations/vertical/MOM_kappa_shear.F90

@@ -1618,7 +1618,7 @@ subroutine find_kappa_tke(N2, S2, kappa_in, Idz, h_Int, dz_Int, dz_h_Int, I_L2_b
         ! Solve for dQ(K)...
         aQ(k) = (0.5*(kappa(K)+kappa(K+1))+kappa0) * Idz(k)
         dQdz(k) = 0.5*(TKE(K) - TKE(K+1))*Idz(k)
-        tke_src = h_Int(K) * (dz_h_Int(K)*((kappa(K) + kappa0)*S2(K) - kappa(k)*N2(K)) - &
+        tke_src = h_Int(K) * ((dz_h_Int(K) * ((kappa(K) + kappa0)*S2(K) - kappa(k)*N2(K))) - &
                                (TKE(k) - q0)*TKE_decay(k)) - &
                   (aQ(k) * (TKE(K) - TKE(K+1)) - aQ(k-1) * (TKE(K-1) - TKE(K)))
         v1 = aQ(k-1) + dQdz(k-1)*dKdQ(K-1)

src/parameterizations/vertical/MOM_vert_friction.F90

@@ -2116,7 +2116,7 @@ subroutine find_coupling_coef(a_cpl, hvel, do_i, h_harm, bbl_thick, kv_bbl, z_i,
       endif
 
       ! Calculate the coupling coefficients from the viscosities.
-      a_cpl(i,K) = Kv_tot(i,K) / (h_shear + I_amax*Kv_tot(i,K))
+      a_cpl(i,K) = Kv_tot(i,K) / (h_shear + (I_amax * Kv_tot(i,K)))
     endif ; enddo ; enddo ! i & k loops
   elseif (abs(CS%Kv_extra_bbl) > 0.0) then
     ! There is a simple enhancement of the near-bottom viscosities, but no adjustment