Puma::Cluster#stop_workers - use WNOHANG with nil return tests
Puma::Cluster#stop_workers - use WNOHANG with nil return tests

Ruby 2.6 introduced a bug that affects worker shutdown (waitpid).

Added code using Process::WNOHANG along with needed logic. Adds worker status (via $?) and total shutdown time to log.

Co-authored-by: MSP-Greg <9abfdc20211b0ed870023ccf9fa185e226f4206e@gmail.com>
Co-authored-by: guilleiguaran <5282eb8a112e0c62fe591e7e5c0a8d029936dc09@gmail.com>

looker/puma,puma/puma,looker/puma,puma/puma,eileencodes/puma,puma/puma,eileencodes/puma,eileencodes/puma,puma/puma,eileencodes/puma,looker/puma,looker/puma