Update events fire stub.

[moniika]

The basics

• I branched from develop
• My pull request is against develop
• My code follows the style guide

The details

Resolves

Clean up as part of #4070

Proposed Changes

• Update Events fire stub to call original wrapped method rather than custom logic.

Reason for Changes

• Now that async cleanup was added for all tests with Cleanup for asynchronous calls in Blockly tests #4070, calling wrapped method is feasible and better tests the Event.fire logic since its called directly and is less fragile changes to Events.fire

Test Coverage

Ran mocha tests

Tested on:

• Desktop Chrome