Normalized slice should be subclasses for slice.

[kaushikcfd]

This would allow us to use a NormalizedSlice to index into an array.

[kaushikcfd]

Minimal Reproducer:

import pytato as pt
from pytato.array import NormalizedSlice
a = pt.make_placeholder("a", 10)
a[NormalizedSlice(0, 10, 1)] # <- fails

[inducer]

I'd be OK with that.