patch 9.0.0617: calling function for reduce() has too much overhead

Problem:    Calling function for reduce() has too much overhead.
Solution:   Only call clear_tv() when needed.
diff --git a/src/list.c b/src/list.c
index fab86fd..a39c9f9 100644
--- a/src/list.c
+++ b/src/list.c
@@ -3073,10 +3073,12 @@
 
 	r = eval_expr_typval(expr, argv, 2, rettv);
 
-	clear_tv(&argv[0]);
+	if (argv[0].v_type != VAR_NUMBER && argv[0].v_type != VAR_UNKNOWN)
+	    clear_tv(&argv[0]);
 	if (r == FAIL || called_emsg != called_emsg_start)
 	    break;
 
+	// advance to the next item
 	if (range_list)
 	{
 	    range_val += l->lv_u.nonmat.lv_stride;
diff --git a/src/version.c b/src/version.c
index 815f27b..43569d0 100644
--- a/src/version.c
+++ b/src/version.c
@@ -700,6 +700,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    617,
+/**/
     616,
 /**/
     615,
diff --git a/src/vim9execute.c b/src/vim9execute.c
index 1699caf..ddcbe2c 100644
--- a/src/vim9execute.c
+++ b/src/vim9execute.c
@@ -710,7 +710,8 @@
 	    return FAIL;
 
 	funcstack->fs_var_offset = argcount + STACK_FRAME_SIZE;
-	funcstack->fs_ga.ga_len = funcstack->fs_var_offset + dfunc->df_varcount;
+	funcstack->fs_ga.ga_len = funcstack->fs_var_offset
+							  + dfunc->df_varcount;
 	stack = ALLOC_CLEAR_MULT(typval_T, funcstack->fs_ga.ga_len);
 	funcstack->fs_ga.ga_data = stack;
 	if (stack == NULL)
@@ -5881,7 +5882,11 @@
 failed_early:
     // Free all arguments and local variables.
     for (idx = 0; idx < ectx.ec_stack.ga_len; ++idx)
-	clear_tv(STACK_TV(idx));
+    {
+	tv = STACK_TV(idx);
+	if (tv->v_type != VAR_NUMBER && tv->v_type != VAR_UNKNOWN)
+	    clear_tv(tv);
+    }
     ex_nesting_level = orig_nesting_level;
 
     vim_free(ectx.ec_stack.ga_data);
@@ -6371,11 +6376,11 @@
 		break;
 	    case ISN_NEWLIST:
 		smsg("%s%4d NEWLIST size %lld", pfx, current,
-					    (varnumber_T)(iptr->isn_arg.number));
+					  (varnumber_T)(iptr->isn_arg.number));
 		break;
 	    case ISN_NEWDICT:
 		smsg("%s%4d NEWDICT size %lld", pfx, current,
-					    (varnumber_T)(iptr->isn_arg.number));
+					  (varnumber_T)(iptr->isn_arg.number));
 		break;
 	    case ISN_NEWPARTIAL:
 		smsg("%s%4d NEWPARTIAL", pfx, current);