Node.js agent v1.30.1

Bug fixes

• The shutdown method is now on the stub API.

  Previously when the agent was disabled the stub API passed back on require did not have the shutdown method. Thanks goes to Vlad Fedosov (@StyleT) for this contribution!

• Global timers will now be wrapped correctly regardless of being wrapped by something else.

  The logic to check whether to wrap the global timers was looking to see if the global timers were the same function reference as the ones in the timers module. This would break in cases where either the global or timers functions had been wrapped.

• Director instrumentation now correctly handles the case of null route handlers being passed in.

  Previously the agent's director instrumentation would crash in cases of null route handlers in director.