patch 8.2.2381: Vim9: divide by zero does not abort expression execution

Problem:    Vim9: divide by zero does not abort expression execution.
Solution:   Use a "failed" flag. (issue #7704)
diff --git a/src/eval.c b/src/eval.c
index 40c6feb..3e316bd 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -57,16 +57,21 @@
 
 /*
  * Return "n1" divided by "n2", taking care of dividing by zero.
+ * If "failed" is not NULL set it to TRUE when dividing by zero fails.
  */
 	varnumber_T
-num_divide(varnumber_T n1, varnumber_T n2)
+num_divide(varnumber_T n1, varnumber_T n2, int *failed)
 {
     varnumber_T	result;
 
     if (n2 == 0)
     {
 	if (in_vim9script())
+	{
 	    emsg(_(e_divide_by_zero));
+	    if (failed != NULL)
+		*failed = TRUE;
+	}
 	if (n1 == 0)
 	    result = VARNUM_MIN; // similar to NaN
 	else if (n1 < 0)
@@ -82,12 +87,17 @@
 
 /*
  * Return "n1" modulus "n2", taking care of dividing by zero.
+ * If "failed" is not NULL set it to TRUE when dividing by zero fails.
  */
 	varnumber_T
-num_modulus(varnumber_T n1, varnumber_T n2)
+num_modulus(varnumber_T n1, varnumber_T n2, int *failed)
 {
     if (n2 == 0 && in_vim9script())
+    {
 	emsg(_(e_divide_by_zero));
+	if (failed != NULL)
+	    *failed = TRUE;
+    }
     return (n2 == 0) ? 0 : (n1 % n2);
 }
 
@@ -1516,6 +1526,7 @@
     varnumber_T	n;
     char_u	numbuf[NUMBUFLEN];
     char_u	*s;
+    int		failed = FALSE;
 
     // Can't do anything with a Funcref, Dict, v:true on the right.
     if (tv2->v_type != VAR_FUNC && tv2->v_type != VAR_DICT
@@ -1599,8 +1610,10 @@
 			    case '+': n += tv_get_number(tv2); break;
 			    case '-': n -= tv_get_number(tv2); break;
 			    case '*': n *= tv_get_number(tv2); break;
-			    case '/': n = num_divide(n, tv_get_number(tv2)); break;
-			    case '%': n = num_modulus(n, tv_get_number(tv2)); break;
+			    case '/': n = num_divide(n, tv_get_number(tv2),
+							       &failed); break;
+			    case '%': n = num_modulus(n, tv_get_number(tv2),
+							       &failed); break;
 			}
 			clear_tv(tv1);
 			tv1->v_type = VAR_NUMBER;
@@ -1619,7 +1632,7 @@
 		    tv1->v_type = VAR_STRING;
 		    tv1->vval.v_string = s;
 		}
-		return OK;
+		return failed ? FAIL : OK;
 
 	    case VAR_FLOAT:
 #ifdef FEAT_FLOAT
@@ -3196,12 +3209,16 @@
 	    else
 #endif
 	    {
+		int	    failed = FALSE;
+
 		if (op == '*')
 		    n1 = n1 * n2;
 		else if (op == '/')
-		    n1 = num_divide(n1, n2);
+		    n1 = num_divide(n1, n2, &failed);
 		else
-		    n1 = num_modulus(n1, n2);
+		    n1 = num_modulus(n1, n2, &failed);
+		if (failed)
+		    return FAIL;
 
 		rettv->v_type = VAR_NUMBER;
 		rettv->vval.v_number = n1;