patch 8.2.1344: Vim9: No test for trying to redefine global function

Problem:    Vim9: No test for trying to redefine global function.
Solution:   Add a test.

src/testdir/test_vim9_func.vim

@@ -159,6 +159,19 @@ def Test_nested_global_function()
       delfunc g:Inner
   END
   CheckScriptSuccess(lines)
+
+  lines =<< trim END
+      vim9script
+      def Outer()
+          def g:Inner(): string
+              return 'inner'
+          enddef
+      enddef
+      defcompile
+      Outer()
+      Outer()
+  END
+  CheckScriptFailure(lines, "E122:")
 enddef
 
 def Test_global_local_function()

src/version.c

@@ -754,6 +754,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1344,
 /**/
     1343,
 /**/