Disable all the tests that are flaking more than 5% on Windows builders.

mojo/system/message_pipe_dispatcher_unittest.cc

Index: mojo/system/message_pipe_dispatcher_unittest.cc
diff --git a/mojo/system/message_pipe_dispatcher_unittest.cc b/mojo/system/message_pipe_dispatcher_unittest.cc
index 73cbc541a6496886933aaeda2b523c4c60b190f3..95f5bf804764fa57284252505c09afe2dc9836ee 100644
--- a/mojo/system/message_pipe_dispatcher_unittest.cc
+++ b/mojo/system/message_pipe_dispatcher_unittest.cc
@@ -258,7 +258,13 @@ TEST(MessagePipeDispatcherTest, BasicClosed) {
   }
 }
 
-TEST(MessagePipeDispatcherTest, BasicThreaded) {
+#if defined(OS_WIN)
+// http://crbug.com/396386
+#define MAYBE_BasicThreaded DISABLED_BasicThreaded
+#else
+#define MAYBE_BasicThreaded BasicThreaded
+#endif
+TEST(MessagePipeDispatcherTest, MAYBE_BasicThreaded) {
   test::Stopwatch stopwatch;
   int32_t buffer[1];
   const uint32_t kBufferSize = static_cast<uint32_t>(sizeof(buffer));