Turn elems On VMArray Into Direct Memory Access

replace the full function call, which was far
too much overhead just to read an integer at
an offset inside the object.

src/6model/reprs/VMArray.c

@@ -1363,6 +1363,18 @@ static void spesh(MVMThreadContext *tc, MVMSTable *st, MVMSpeshGraph *g, MVMSpes
         }
         break;
     }
+    case MVM_OP_elems: {
+            MVMSpeshOperand target   = ins->operands[0];
+            MVMSpeshOperand obj      = ins->operands[1];
+
+            MVM_spesh_graph_add_comment(tc, g, ins, "specialized from elems on VMArray");
+
+            ins->info                 = MVM_op_get_op(MVM_OP_sp_get_i64);
+            ins->operands             = MVM_spesh_alloc(tc, g, 3 * sizeof(MVMSpeshOperand));
+            ins->operands[0]          = target;
+            ins->operands[1]          = obj;
+            ins->operands[2].lit_i16 = offsetof(MVMArray, body.elems);
+    }
     }
 }