user32/tests: Close event at the end of the test_WaitForInputIdle test.

There's some random timeout failures on Windows VMs in this test, this
is probably not going to fix them, but cleaning up is not going to hurt.

Signed-off-by: Rémi Bernon <rbernon@codeweavers.com>
Signed-off-by: Alexandre Julliard <julliard@winehq.org>

dlls/user32/tests/msg.c

@@ -16315,6 +16315,7 @@ static void test_WaitForInputIdle( char *argv0 )
             CloseHandle( pi.hThread );
         }
     }
+    CloseHandle( end_event );
     CloseHandle( start_event );
     PostThreadMessageA( id, WM_QUIT, 0, 0 );
     WaitForSingleObject( thread, 10000 );