Add ManagedRuntimeEventSource (#22515)
* Adding a dummy ManagedRuntimeEventSource
* Add ManagedRuntimeEventSource
* Renaming ManagedRuntimeEventSource to RuntimeEventSource
* some cleanup
* use Condition instead of ifdefing out the whole file
* some cleanups
* remove unused namespaces
* Move m_RuntimeEventSource to RuntimeEventSource from EventPipeController
* Adding some TODO items
* address more pr comments
* Use GUID to initialize RuntimeEventSource
* Exclude BasicEventSourceTests from CoreFX test CI leg
* Addressing rest of the PR feedback
* dont dispose counters on disable command to avoid races