Instrument and test Concurrent::ScheduledTask#execute

[kaylareopelle]

Acceptance Criteria

• Add a segment to the existing transaction or create a new transaction when Concurrent::ScheduledTask#execute is called
  • If the method starts a transaction, it should have a non-web type
  • This is different from the others because it’s more likely to take place outside of a transaction-creating library call

Resources

• https://ruby-concurrency.github.io/concurrent-ruby/1.1.4/Concurrent/ScheduledTask.html
• https://github.com/ruby-concurrency/concurrent-ruby/blob/385156117c110808875e1e87d5267147f696f796/lib/concurrent-ruby/concurrent/scheduled_task.rb#L280-L292

[workato-integration]

https://issues.newrelic.com/browse/NEWRELIC-5451

[kaylareopelle]

Blocked by #1602

[kaylareopelle]

#1602 is complete! All clear. Please branch off concurrent_ruby

[kaylareopelle]

#1601 covers Concurrent::ScheduledTask#execute because RubyExecutorService#post is invoked by Concurrent::ScheduledTask#execute. We don't need special instrumentation for this method if we instrument RubyExecutorService#post.

@hannahramadan - We should still add this method to our playground applications to run thorough tests on this method.