KWSys: Update to version as of 2021-10-27
In particular, integrate utils/kwsys!235 (merged), but not utils/kwsys!236 (merged) yet.
This is !6668 (closed) without the FileExists change, which is pending further discussion.
In particular, integrate utils/kwsys!235 (merged), but not utils/kwsys!236 (merged) yet.
This is !6668 (closed) without the FileExists change, which is pending further discussion.