Testing crashes randomly

[cpunion]

When call runtime.GC() after every case, some case crashes randomly, currently workaround by disable automatic DecRef.

func setupTest(t *testing.T) {
	testMutex.Lock()
	Initialize()
	// TODO: Remove this once we solve random segfaults
	getGlobalData().disableDecRef = true
	t.Cleanup(func() {
		runtime.GC()
		Finalize()
		testMutex.Unlock()
	})
}

Need locate the problem.

[cpunion]

Fix by #22