patch 8.2.3404: Vim9: no error for white space before "("

Problem:    Vim9: no error for white space before "(".
Solution:   Give an error, like in a compiled function.
diff --git a/src/testdir/test_vim9_func.vim b/src/testdir/test_vim9_func.vim
index f0c4c0d..09f80e9 100644
--- a/src/testdir/test_vim9_func.vim
+++ b/src/testdir/test_vim9_func.vim
@@ -467,6 +467,10 @@
   MyVarargs('one', 'two', 'three')->assert_equal('one,two,three')
 enddef
 
+def Test_call_white_space()
+  CheckDefAndScriptFailure2(["call Test ('text')"], 'E476:', 'E1068:')
+enddef
+
 def MyDefaultArgs(name = 'string'): string
   return name
 enddef
diff --git a/src/userfunc.c b/src/userfunc.c
index 4a2b05e..aa55bc8 100644
--- a/src/userfunc.c
+++ b/src/userfunc.c
@@ -4921,13 +4921,16 @@
     // Skip white space to allow ":call func ()".  Not good, but required for
     // backward compatibility.
     startarg = skipwhite(arg);
-    rettv.v_type = VAR_UNKNOWN;	// clear_tv() uses this
-
     if (*startarg != '(')
     {
 	semsg(_(e_missing_paren), eap->arg);
 	goto end;
     }
+    if (in_vim9script() && startarg > arg)
+    {
+	semsg(_(e_no_white_space_allowed_before_str_str), "(", eap->arg);
+	goto end;
+    }
 
     /*
      * When skipping, evaluate the function once, to find the end of the
@@ -4969,6 +4972,7 @@
 	funcexe.partial = partial;
 	funcexe.selfdict = fudi.fd_dict;
 	funcexe.check_type = type;
+	rettv.v_type = VAR_UNKNOWN;	// clear_tv() uses this
 	if (get_func_tv(name, -1, &rettv, &arg, &evalarg, &funcexe) == FAIL)
 	{
 	    failed = TRUE;
diff --git a/src/version.c b/src/version.c
index 97467aa..cfddf6b 100644
--- a/src/version.c
+++ b/src/version.c
@@ -756,6 +756,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    3404,
+/**/
     3403,
 /**/
     3402,