Remove the constraint that min / max should stride zero

Since we apply nudging for the zero point to make sure the nudged zerop points
can be in the range of [qmin, qmax], the constraint that rmin / rmax should
stride zero isn't necessary.

This also matches the documentation of tensorflow's FakeQuantWithMinMaxArgs op,
where min and max don't need to stride zero:
https://www.tensorflow.org/api_docs/python/tf/quantization/fake_quant_with_min_max_args

PiperOrigin-RevId: 268296285