patch 9.1.0384: tests: vt420 terminfo entry may not be found

Problem:  tests: vt420 terminfo entry may not be found
          (Shane-XB-Qian)
Solution: check existence of terminfo vt420 and infocmp command

related: #14595
closes: #14677

Signed-off-by: Christian Brabandt <cb@256bit.org>

src/testdir/test_terminal3.vim

@@ -935,7 +935,14 @@ func Test_terminal_vt420()
   CheckRunVimInTerminal
   " For Termcap
   CheckUnix
-  let rows=15
+  CheckExecutable infocmp
+  let a = system('infocmp vt420')
+  if v:shell_error
+     " reset v:shell_error
+     let a = system('true')
+     throw 'Skipped: vt420 terminfo not available'
+  endif
+  let rows = 15
   call writefile([':set term=vt420'], 'Xterm420', 'D')
 
   let buf = RunVimInTerminal('-S Xterm420', #{rows: rows})

src/version.c

@@ -704,6 +704,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    384,
 /**/
     383,
 /**/