[BUG] approx_percentile returns array of zero percentiles instead of null in some cases

[andygrove]

Describe the bug

I just saw this while debugging another issue. The rows here are CPU exact, CPU approx, GPU approx. GPU should have returned None as well.

Row(k='oy\x08Y£àK<', the_percentile=None)
Row(k='oy\x08Y£àK<', the_percentile=None)
Row(k='oy\x08Y£àK<', the_percentile=[0.0, 0.0, 0.0, 0.0, 0.0])

Steps/Code to reproduce bug
TBD I am working on improving the integration tests to catch this.

Expected behavior
CPU and GPU should match.

Environment details (please complete the following information)
N/A

Additional context
N/A

[andygrove]

We have also seen illegal memory access errors related to this issue