patch 8.2.2378: Vim9: no error message for dividing by zero

Problem:    Vim9: no error message for dividing by zero.
Solution:   Give an error message. (issue #7704)
diff --git a/src/vim9execute.c b/src/vim9execute.c
index 907a52f..b1bc282 100644
--- a/src/vim9execute.c
+++ b/src/vim9execute.c
@@ -2954,10 +2954,16 @@
 			switch (iptr->isn_arg.op.op_type)
 			{
 			    case EXPR_MULT: n1 = n1 * n2; break;
-			    case EXPR_DIV:  n1 = num_divide(n1, n2); break;
+			    case EXPR_DIV:  n1 = num_divide(n1, n2);
+					    if (n2 == 0)
+						goto on_error;
+					    break;
 			    case EXPR_SUB:  n1 = n1 - n2; break;
 			    case EXPR_ADD:  n1 = n1 + n2; break;
-			    default:	    n1 = num_modulus(n1, n2); break;
+			    default:	    n1 = num_modulus(n1, n2);
+					    if (n2 == 0)
+						goto on_error;
+					    break;
 			}
 			clear_tv(tv1);
 			clear_tv(tv2);