patch 8.1.0092: prompt buffer test fails

Problem:    Prompt buffer test fails.
Solution:   Set 'nomodified' before closing the window. (Ozaki Kiichi,
            closes #3051

src/testdir/test_prompt_buffer.vim

@@ -24,6 +24,8 @@ func WriteScript(name)
   call writefile([
 	\ 'func TextEntered(text)',
 	\ '  if a:text == "exit"',
+	\ '    " Reset &modified to allow the buffer to be closed.',
+	\ '    set nomodified',
 	\ '    stopinsert',
 	\ '    close',
 	\ '  else',

src/version.c

@@ -761,6 +761,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    92,
 /**/
     91,
 /**/