[Chapel Merge] Fix scans of DR slices of Block arrays

Branch: refs/heads/main
Revision: b01437f
Author: bradcray
Link: Fix scans of DR slices of Block arrays by bradcray · Pull Request #20029 · chapel-lang/chapel · GitHub
Log Message:

Merge pull request #20029 from bradcray/fix-scan-of-DR-slice-of-block

Fix scans of DR slices of Block arrays

[reviewed by @ronawho]

This fixes a bug with scans of DR slices of 1D Block arrays that
stems from having used a non-portable way to get at the domain
representing the target locales. It also adds a test to lock in this
behavior going forward. This was discovered while looking into
a proposed block-scan optimization that Elliot developed as we
were reasoning through whether we could assume that the arrays/
domains would be block.

Modified Files:
A test/scan/scanDRSliceOfBlock.chpl

A test/scan/scanDRSliceOfBlock.good
A test/scan/scanDRSliceOfBlock.numlocales
M modules/dists/BlockDist.chpl

Compare: https://github.com/chapel-lang/chapel/compare/d8c48efbeeec...b01437ffc2d7