TestDurationToKillTime is flaky

[asobti]

Fails occasionally because the result of the test is time-dependent:

kube-monkey/chaos/chaos_test.go

Lines 149 to 152 in ebe3dbf

	func (s *ChaosTestSuite) TestDurationToKillTime() {
	t := s.chaos.DurationToKillTime()
	s.WithinDuration(s.chaos.KillAt(), time.Now(), t+time.Millisecond)
	}

--- FAIL: TestSuite (0.02s)
    --- FAIL: TestSuite/TestDurationToKillTime (0.00s)
    	chaos_test.go:151: 
    			Error Trace:	chaos_test.go:151
    			Error:      	Max difference between 2018-11-25 05:07:14.010708836 +0000 UTC m=+0.017815678 and 2018-11-25 05:07:14.011653307 +0000 UTC m=+0.018760214 allowed is 57.703µs, but difference was -944.536µs
    			Test:       	TestSuite/TestDurationToKillTime

[asobti]

Disabled test in #133 until it is fixed