patch 8.0.1055: bufline test hangs on MS-Windows

Problem:    Bufline test hangs on MS-Windows.
Solution:   Avoid message for writing file.  Source shared.vim when running
            test individually.

src/testdir/test_bufline.vim

@@ -1,5 +1,9 @@
 " Tests for setbufline() and getbufline()
 
+if !exists('*GetVimCommand')
+  source shared.vim
+endif
+
 func Test_setbufline_getbufline()
   new
   let b = bufnr('%')
@@ -30,7 +34,7 @@ func Test_setline_startup()
   if cmd == ''
     return
   endif
-  call writefile(['call setline(1, "Hello")', 'w Xtest', 'q!'], 'Xscript')
+  call writefile(['call setline(1, "Hello")', 'silent w Xtest', 'q!'], 'Xscript')
   call system(cmd)
   call assert_equal(['Hello'], readfile('Xtest'))
 

src/testdir/test_timers.vim

@@ -4,6 +4,10 @@ if !has('timers')
   finish
 endif
 
+if !exists('*WaitFor')
+  source shared.vim
+endif
+
 func MyHandler(timer)
   let g:val += 1
 endfunc

src/version.c

@@ -769,6 +769,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1055,
 /**/
     1054,
 /**/