ENH: add non-const access for lduMatrix::solverPerformance::solverName()

- use it to report the correct solverName for vector/tensor fields

src/OpenFOAM/matrices/lduMatrix/lduMatrix/lduMatrix.H

@@ -145,6 +145,13 @@ public:
                 return solverName_;
             }
 
+            //- Return solver name
+            word& solverName()
+            {
+                return solverName_;
+            }
+
+
             //- Return initial residual
             scalar initialResidual() const
             {

src/finiteVolume/fvMatrices/fvMatrix/fvMatrixSolve.C

@@ -150,6 +150,7 @@ Foam::lduMatrix::solverPerformance Foam::fvMatrix<Type>::solve
         solverPerf.print();
 
         solverPerfVec = max(solverPerfVec, solverPerf);
+        solverPerfVec.solverName() = solverPerf.solverName();
 
         psi.internalField().replace(cmpt, psiCmpt);
         diag() = saveDiag;