patch 8.1.2167: mapping test fails on MS-Windows

Problem:    Mapping test fails on MS-Windows.
Solution:   Remove all the existing Insert-mode mappings.

Author: brammool

src/testdir/test_mapping.vim

@@ -444,8 +444,8 @@ func Test_error_in_map_expr()
 endfunc
 
 func Test_list_mappings()
-  " Remove default Mac mapping
-  silent! iunmap <D-v>
+  " Remove default mappings
+  imapclear
 
   inoremap <C-M> CtrlM
   inoremap <A-S> AltS

src/version.c

@@ -753,6 +753,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    2167,
 /**/
     2166,
 /**/