Improve wait for delays on shutdown

[jgaalen]

Description

Improve the time for a shutdown when there are significant delays.

Motivation and Context

Currently, when shutting down a test, it waits for all the timer/delays to finish. They can take a long time as it just waits for the sleep to complete. Now the sleep behaviour is the same as ramp up sleeps with checks on the test running in between. Now shutting down a test (gracefully) is a lot quicker when you have significant delays in your test.

How Has This Been Tested?

Manually

Screenshots (if appropriate):

Types of changes

Added jmeterthread.timer.granularity to update the interval of checking if a test is stopped

Checklist:

• My code follows the code style of this project.
• I have updated the documentation accordingly.