patch 9.0.0405: arguments in a partial not used by a :def function

Problem:    Arguments in a partial not used by a :def function.
Solution:   Put the partial arguments on the stack.
diff --git a/src/userfunc.c b/src/userfunc.c
index 76ab6b9..1902778 100644
--- a/src/userfunc.c
+++ b/src/userfunc.c
@@ -2653,7 +2653,7 @@
 	    profile_may_start_func(&profile_info, fp, caller);
 #endif
 	sticky_cmdmod_flags = 0;
-	call_def_function(fp, argcount, argvars, funcexe->fe_partial,
+	call_def_function(fp, argcount, argvars, 0, funcexe->fe_partial,
 								    fc, rettv);
 	funcdepth_decrement();
 #ifdef FEAT_PROFILE