The start/end offsets are not necessarily coterminous with the underlying
values array, so even if the stride is fixed, we still we need to slice
the chunks down to match the start/end offsets.
This bug shouldn't affect the correctness of any existing code, since
we're always working with unsliced arrays read directly from Parquet.
Change-Id: I2f7ddc4e66d4d3b2317a44bd436a35bff36bac79
Reviewed-on: https://cl.tvl.fyi/c/depot/+/11081
Tested-by: BuildkiteCI
Reviewed-by: flokli <flokli@flokli.de>
