[Chapel Merge] Limit to building with 4 cores on test macs

Branch: refs/heads/main
Revision: 067f7bd60ea2054b2425672e1a90ff4cecf7603d
Author: arifthpe
Link: Limit to building with 4 cores on test macs by arifthpe · Pull Request #28768 · chapel-lang/chapel · GitHub
Log Message:
Limit to building with 4 cores on test macs (#28768)

We are getting OOMs on our testing Macs, so limit to using 4 cores in
tests on those systems.

[reviewed by @jabraham17, thanks!]

Compare: Comparing 9d7e5103a5fa0827318ff78f804e901f7260979f...85e5f06423851c8d90f9442fbb29c058d65363b9 · chapel-lang/chapel · GitHub

Diff:
M util/cron/common-darwin.bash
https://github.com/chapel-lang/chapel/pull/28768.diff