patch 8.1.2118: termcodes test fails when $TERM is "dumb"

Problem:    Termcodes test fails when $TERM is "dumb".
Solution:   Skip the test. (James McCoy, closes #5019)

src/testdir/test_termcodes.vim

@@ -798,7 +798,11 @@ func Test_xx_term_style_response()
 endfunc
 
 func Test_get_termcode()
-  let k1 = &t_k1
+  try
+    let k1 = &t_k1
+  catch /E113/
+    throw 'Skipped: Unable to query termcodes'
+  endtry
   set t_k1=
   set t_k1&
   call assert_equal(k1, &t_k1)

src/version.c

@@ -753,6 +753,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    2118,
 /**/
     2117,
 /**/