InEpsilon does not fail when passed a NaN value

[hectorj]

Hi! We ran into a small isue today with require.InEpsilon, at version 1.5.1

func TestInEpsilonNaN(t *testing.T) {
	require.InEpsilon(t, 42, math.NaN(), 1)
}

Actual result : test passes

Expected result : an error

[hectorj]

This is highly similar to #162

I'll make a PR with the equivalent changes

[ybrustin-te]

func TestInEpsilon1(t *testing.T) {
	div := 0.0
	require.InEpsilon(t, 1, 1/div, 0.001)
}

func TestInEpsilon2(t *testing.T) {
	div := 0.0
	require.InEpsilon(t, 1/div, 1, 0.001)
}

> go test -v -run InEps | grep -E '(PASS|FAIL)'
--- FAIL: TestInEpsilon1 (0.00s)
--- PASS: TestInEpsilon2 (0.00s)