patch 8.2.2959: sound_playfile() is not tested on MS-Windows

Problem:    sound_playfile() is not tested on MS-Windows.
Solution:   Make it work and enable the test. (Dominique Pellé, closes #8338)
diff --git a/src/testdir/test_sound.vim b/src/testdir/test_sound.vim
index cc01bf6..ff58262 100644
--- a/src/testdir/test_sound.vim
+++ b/src/testdir/test_sound.vim
@@ -75,17 +75,15 @@
 endfunc
 
 func Test_play_event_error()
-  " Do not run test on Windows as:
-  " - playing event with callback is not supported on Windows.
-  " - FIXME: even without callback, sound_playevent('') does not return 0 on Windows. Bug?
-  CheckNotMSWindows
-
-  call assert_equal(0, sound_playevent(''))
-  call assert_equal(0, sound_playevent(test_null_string()))
-  call assert_equal(0, sound_playevent('doesnotexist'))
-  call assert_equal(0, sound_playevent('doesnotexist', 'doesnotexist'))
-  call assert_equal(0, sound_playevent(test_null_string(), test_null_string()))
-  call assert_equal(0, sound_playevent(test_null_string(), test_null_function()))
+  " FIXME: sound_playevent() doesn't return 0 in case of error on Windows.
+  if !has('win32')
+    call assert_equal(0, sound_playevent(''))
+    call assert_equal(0, sound_playevent(test_null_string()))
+    call assert_equal(0, sound_playevent('doesnotexist'))
+    call assert_equal(0, sound_playevent('doesnotexist', 'doesnotexist'))
+    call assert_equal(0, sound_playevent(test_null_string(), test_null_string()))
+    call assert_equal(0, sound_playevent(test_null_string(), test_null_function()))
+  endif
 
   call assert_equal(0, sound_playfile(''))
   call assert_equal(0, sound_playfile(test_null_string()))