[Chapel Merge] Make PCGRandomLib private by default

Branch: refs/heads/master
Revision: 592ff8e
Author: bradcray
Log Message:

Merge pull request #16501 from bradcray/private-pcg-rand-lib-take-2

Make PCGRandomLib private by default

[trivial, not reviewed; @mppf proposed the change]

Michael pointed this out in #16119, though it was not unique to that PR
or related to its intent, so I saved it for a separate PR.

This required extending the current ISx benchmarks to make them
use it explicitly (is it appropriate that they do so?), and updating
some tests of the PCG stream’s internals (which seems completely

Modified Files:
M modules/standard/Random.chpl
M test/classes/ferguson/forwarding/isx-bug.chpl
M test/library/standard/Random/ferguson/pcg-rand-check.chpl
M test/library/standard/Random/ferguson/pcg-rand-range-check.chpl
M test/library/standard/Random/ferguson/pcg-rand-range-check2.chpl
M test/release/examples/benchmarks/isx/isx.chpl
M test/studies/isx/isx-bucket-spmd.chpl
M test/studies/isx/isx-hand-optimized.chpl
M test/studies/isx/isx-no-return.chpl
M test/studies/isx/isx-per-task.chpl

Compare: https://github.com/chapel-lang/chapel/compare/e1c617971cbf...592ff8e7f2ef