[Fuzzing] `FuzzGetBin` reports error

[pellared]

The FuzzGetBin failed with:

v=0x1p-1069 scale =6 had bin -68417, but was below lower bound 0x1p-1069

From OSS Fuzz: https://issues.oss-fuzz.com/issues/421943271

Reproducing OSS-Fuzz issues

clusterfuzz-testcase-minimized-FuzzGetBin-5058674567741440.txt (added .txt suffix)

[pellared]

CC @dashpole

[pellared]

This will reproduce the fuzz failure:

func TestGetBin(t *testing.T) {
	v := 0x1p-1069
	p := newExpoHistogramDataPoint[float64](alice, 4, 20, false, false)
	p.scale = 6
	got := p.getBin(v)
	if v <= lowerBound(got, p.scale) {
		t.Errorf(
			"v=%x scale =%d had bin %d, but was below lower bound %x",
			v,
			p.scale,
			got,
			lowerBound(got, p.scale),
		)
	}
	if v > lowerBound(got+1, p.scale) {
		t.Errorf(
			"v=%x scale =%d had bin %d, but was above upper bound %x",
			v,
			p.scale,
			got,
			lowerBound(got+1, p.scale),
		)
	}
}

[dashpole]

oooh, i'll take a look