Remove SOS and lldb plugin from the coreclr repo

[mikem8361]

SOS and the lldb plugin now live in the diagnostics repo. We are almost ready to remove them from the coreclr repo probably in the Preview 6 time frame.

We are still waiting for the new SOS to shipping with the next public release of the Windows debugger (windbg) and there are still some OS/architecture holes in the diagnostics repo's build (and test) matrix (i.e. arm, arm64, FreeBSD, etc.).

[stephentoub]

@tommcdon removed this from the 3.0 milestone

Does this mean an SOS built out of the coreclr repo is going to ship in 3.0? If so, I want to port from the diagnostics repo some changes that were made only there when it was stated that SOS would not ship out of dotnet/coreclr in 3.0.

[mikem8361]

I still won't bother with merging the changes into coreclr. The diagnostics repo SOS has a lot of new features and fixes that coreclr doesn't.

I need to discuss this with Tom, but I still do want to remove SOS from coreclr in the Preview 7 timeframe otherwise it will probably ship with 3.0.

[mikem8361]

SOS is ready to remove from the runtime/coreclr repo when:

• All SOS commands ported and working in diagnostics repo
• Windows x64, x86 and arm supported and tested
• Linux x64 supported and tested
• Linux arm and arm64 supported and tested
• Linux MUSL based distros (i.e. Alpine) supported
• Windows SOS published in the internal extension gallery
• Windows SOS shipped with the latest public/external Windows debugger release
• Out of band SOS installation for Linux and macOS (dotnet-sos) finished
• Document how to install SOS on Windows, Linux and macOS
• Note added to coreclr repo pointing to the diagnostics repo SOS source.
• Note added to the runtime package (Microsoft.NETCore.App) explaining how to get SOS now.

[tommcdon]

@mikem8361 I've moved the issue back to 3.0. Thanks for putting together the release checklist!