patch 8.2.4437: vartabs test fails on MS-Windows

Problem:    Vartabs test fails on MS-Windows.
Solution:   Use iso8859-1 'encoding'. (Ken Takata, closes #9818)

Author: k-takata

src/testdir/test_vartabs.vim

@@ -445,10 +445,10 @@ endfunc
 func Test_vartabstop_latin1()
   let save_encoding = &encoding
   new
-  set encoding=iso8859
-  silent norm :se 
+  set encoding=iso8859-1
+  silent exe "norm :se \<C-A>\<C-C>"
   set vartabstop=400
-  norm i00	
+  exe "norm i00\t\<C-D>"
   bwipe!
   let &encoding = save_encoding
 endfunc

src/version.c

@@ -750,6 +750,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    4437,
 /**/
     4436,
 /**/