Remove cohosting setting and hardcode the value to true

[davidwengier]

Part of dotnet/razor#12491

Removes the bits of the C# extension that are for the non-cohosting editor. The OmniSharp setting still works as normal. I did it in bits, so commit-at-a-time might make sense, but most of it is just deleting whole files so GitHub hopefully will do a decent job.

There is a bit more cleanup that could happen, and could move some things around now that there is only one Razor system, could remove the word "cohost" from everything etc. but didn't want to make the PR too painful. Will need follow ups anyway, as bits form Roslyn and Razor are removed etc.

Reduces the VSIX size by about 40mb. I'll be honest, I was hoping for more :P

[dibarbet]

can you also drop down the max vsix size on teh artifact tests, so we don't lose the improvement?
https://github.com/dotnet/vscode-csharp/blob/main/test/lsptoolshost/artifactTests/vsix.test.ts

[dibarbet]

since we're deleting so much code I would also be curious if there is an improvement to the extension code load time. You can see the numbers via the perfview.show command. For example for the current version on my machine

[davidwengier]

Not as exciting as I would have hoped, but with both from local builds of the extension:
main:

Extension	Eager	Load Code	Call Activate	Finish Activate	Event	By
ms-dotnettools.csharp	true	516	2	131	workspaceContains:**/*.{csproj,csx,cake}	ms-dotnettools.csharp

this branch:

Extension	Eager	Load Code	Call Activate	Finish Activate	Event	By
ms-dotnettools.csharp	true	456	2	125	workspaceContains:**/*.{csproj,csx,cake}	ms-dotnettools.csharp

What's perhaps more interesting is that "Finish Activate" time was dreadful until I manually deleted my local .razor and .razorDevKit folders. Which I can't really explain, as nothing should have been looking for files in them regardless. Maybe timing on local builds is just flaky.

[dibarbet]

What's perhaps more interesting is that "Finish Activate" time was dreadful until I manually deleted my local .razor and .razorDevKit folders. Which I can't really explain, as nothing should have been looking for files in them regardless. Maybe timing on local builds is just flaky.

interesting! -50ms isn't too bad (still have a lot of O# code). will try it out once we have an official build as well