CI: JRuby v9.4.x.x issues

[fallwith]

At least the latest 2 (v9.4.4.0 and v9.4.3.0) JRuby releases are seeing failures when running through our JRuby specific GitHub Actions CI tests.

We are currently operating under the understanding that these issues:

• Only impact CI behavior, not real world agent usage
• Only take place with GitHub Actions run, and are difficult to reproduce with JRuby on a local workstation

Hypothesis: the issues seem to be caused by the tests' use of a Ruby global, $collector, to serve as a fake collector object (one that can't really send collected data up to New Relic's servers). With JRuby, $collector.calls_for('subject') occasionally return 2 calls instead of 1. If we relax the "exactly 1 should be seen" assertion to "at least 1 should be seen" and operate on the first call seen, everything works.

We could put this method into a test helper and refactor all $collector.calls_for calls in every test:

# instead of
calls = $collector.calls_for(subject)
assert_equal(1, calls.size)

# use the helper
call = first_call_for(subject)

def first_call_for(subject)
  items = $collector.calls_for(subject)

  if defined?(JRUBY_VERSION)
    refute_predicate items.size, :zero?
  else
    assert_equal(1, items.size)
  end

  items.first
end

We could also troubleshoot why there is more than 1 call seen. But unfortunately the fact that this behavior is not reproducible locally and sporadic in where it appears in GitHub Actions, it's a tough one to narrow down.

[workato-integration]

https://new-relic.atlassian.net/browse/NR-174463

[fallwith]

resolved with #2282