Remove Newton Cholesky factor from mjData arena, rollback of b66da3d369.

PiperOrigin-RevId: 685726867
Change-Id: Ic2afd0dd35e38f403164d2cbe4618286abfa51ab

src/engine/engine_core_constraint.c

@@ -1917,7 +1917,7 @@ static int mj_nc(const mjModel* m, mjData* d, int* nnz) {
 // driver: call all functions above
 void mj_makeConstraint(const mjModel* m, mjData* d) {
   // clear sizes
-  d->ne = d->nf = d->nl = d->nefc = d->nnzJ = d->nnzL = 0;
+  d->ne = d->nf = d->nl = d->nefc = d->nnzJ = 0;
 
   // disabled or Jacobian not allocated: return
   if (mjDISABLED(mjDSBL_CONSTRAINT)) {

src/engine/engine_io.c

@@ -1802,7 +1802,6 @@ static void _resetData(const mjModel* m, mjData* d, unsigned char debug_value) {
   d->nl = 0;
   d->nefc = 0;
   d->nnzJ = 0;
-  d->nnzL = 0;
   d->nisland = 0;
 
   // clear global properties

src/engine/engine_print.c

@@ -1180,13 +1180,6 @@ void mj_printFormattedData(const mjModel* m, mjData* d, const char* filename,
     printSparse("EFC_J", d->efc_J, d->nefc, d->efc_J_rownnz,
                 d->efc_J_rowadr, d->efc_J_colind, fp, float_format);
 
-    if (d->nnzL) {
-      // L sparse structure
-      printSparsity("L: Newton reverse Cholesky factor", m->nv, m->nv,
-               d->L_rowadr, d->L_rownnz, d->L_colind, fp);
-      printSparse("L", d->L, m->nv, d->L_rownnz, d->L_rowadr, d->L_colind, fp, float_format);
-    }
-
     printArrayInt("EFC_AR_ROWNNZ", d->nefc, 1, d->efc_AR_rownnz, fp);
     printArrayInt("EFC_AR_ROWADR", d->nefc, 1, d->efc_AR_rowadr, fp);
     printSparse("EFC_AR", d->efc_AR, d->nefc, d->efc_AR_rownnz,