patch 8.2.1418: Vim9: invalid error for missing white space

Problem:    Vim9: invalid error for missing white space after function.
Solution:   Do not skip over white space. (closes #6679)
diff --git a/src/userfunc.c b/src/userfunc.c
index 7d3039a..f38c978f 100644
--- a/src/userfunc.c
+++ b/src/userfunc.c
@@ -686,7 +686,10 @@
     while (--argcount >= 0)
 	clear_tv(&argvars[argcount]);
 
-    *arg = skipwhite(argp);
+    if (in_vim9script())
+	*arg = argp;
+    else
+	*arg = skipwhite(argp);
     return ret;
 }
 
@@ -4097,6 +4100,7 @@
     if (!failed || eap->cstack->cs_trylevel > 0)
     {
 	// Check for trailing illegal characters and a following command.
+	arg = skipwhite(arg);
 	if (!ends_excmd2(eap->arg, arg))
 	{
 	    if (!failed)