Use the same tracked contexts for event pipe and ETW in nativeaot

[elinor-fung]

• Make tracking for event pipe and ETW enabled/status use the same contexts
  • Move event pipe context / callback out of dotnetruntime.cpp and into eventtrace.cpp
    • 42801a9 is just copying the functions
  • Pull out the shared pieces of the callbacks into the common function (similar to coreclr - with the thought that we can eventually unfork the two)
    • 5aafe42 updates the copied functions
  • Remove RH_ETW_CONTEXT and switch to MCGEN_TRACE_CONTEXT, which is what would be generated when nativeaot eventually gets onto the generation scripts
• Switch to using the .NET ETW provider GUIDs instead of .NET Native
  • Rename the handles / contexts to be DotNETRuntime instead of GC - most of the changes in EtwEvents.h were just this
• Implement ep_rt_providers_validate_all_disabled (uses the contexts)

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Issue Details

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• Make tracking for event pipe and ETW enabled/status use the same contexts
  • Move event pipe context / callback out of dotnetruntime.cpp and into eventtrace.cpp
  • Pull out the shared pieces of the callbacks into the common function (similar to coreclr - with the thought that we can eventually unfork the two)
  • Remove RH_ETW_CONTEXT and switch to MCGEN_TRACE_CONTEXT, which is what would be generated when nativeaot eventually gets onto the generation scripts
• Switch to using the .NET ETW provider GUIDs instead of .NET Native
  • Rename the handles / contexts to be DotNETRuntime instead of GC - most of the changes in EtwEvents.h were just this
• Implement ep_rt_providers_validate_all_disabled (uses the contexts)

Author:	elinor-fung
Assignees:	-
Labels:	area-NativeAOT-coreclr
Milestone:	-

[LakshanF]

TLGTM. Thanks for these series of changes making ETW opt-in, the design coherent through the convoluted history and making it easier for us to switch to the python source gen to get ready for enabling future events easier!