Intent of event.test|title=Event Emitter, handles removal during 3|occurrence=1

All 4 exact tests in this concept. Every test is marked by where it enters the hierarchy.

mocha:v1|namespace=vscode@05c208e9e28d8c1c723fa08f85e2b7a96092e8e5|file=vs/ 4 tests
- base/ 4 tests
  - test/ 4 tests
    
    common/ 4 tests
    
    mocha:v1|namespace=vscode@05c208e9e28d8c1c723fa08f85e2b7a96092e8e5|file=vs/base/test/common/event.test|title=Event Emitter duplicate functions|occurrence=1 Inherited event.test|title=Event Emitter duplicate functions|occurrence=1
    
    mocha:v1|namespace=vscode@05c208e9e28d8c1c723fa08f85e2b7a96092e8e5|file=vs/base/test/common/event.test|title=Event Emitter, dispose listener during emission|occurrence=1 Inherited event.test|title=Event Emitter, dispose listener during emission|occurrence=1
    
    mocha:v1|namespace=vscode@05c208e9e28d8c1c723fa08f85e2b7a96092e8e5|file=vs/base/test/common/event.test|title=Event Emitter, handles removal during 3|occurrence=1 Introduced here
    
    mocha:v1|namespace=vscode@05c208e9e28d8c1c723fa08f85e2b7a96092e8e5|file=vs/base/test/common/event.test|title=Event utils issue #230401|occurrence=1 Inherited event.test|title=Event utils issue #230401|occurrence=1