patch 9.1.1174: tests: Test_complete_cmdline() may fail

Problem:  tests: when the file 'TestCommand?Test' exists,
          'Test_complete_cmdline()' will fail when writing the file. And
          there's no related cleaning operation for this kind of file
          before the test run.
Solution: modify `write` to `write!` to override (Jim Zhou).

closes: #16799

Signed-off-by: Jim Zhou <jimzhouzzy@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

src/testdir/test_ins_complete.vim

@@ -1179,8 +1179,8 @@ func Test_complete_cmdline()
   call assert_equal('abcxyz(', getline(3))
   com! -buffer TestCommand1 echo 'TestCommand1'
   com! -buffer TestCommand2 echo 'TestCommand2'
-  write TestCommand1Test
-  write TestCommand2Test
+  write! TestCommand1Test
+  write! TestCommand2Test
   " Test repeating <CTRL-X> <CTRL-V> and switching to another CTRL-X mode
   exe "normal oT\<C-X>\<C-V>\<C-X>\<C-V>\<C-X>\<C-F>\<Esc>"
   call assert_equal('TestCommand2Test', getline(4))

src/version.c

@@ -704,6 +704,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1174,
 /**/
     1173,
 /**/