Use node's ipc for desktop TypeScript server

[mjbvz]

On desktop, VS Code currently communicates with the TypeScript server by passing messages over stdio. These messages are in a json rcp style format

We should instead explore using node's built-in ipc support which would let the two processes communicate using .send and .on('message', ...)

Advantages

• JSON is exchanged directly so we can get rid of this parsing logic on the VS Code side: https://github.com/microsoft/vscode/blob/53350bc6661449bc097496b04a1d8712474bd301/extensions/typescript-language-features/src/tsServer/serverProcess.electron.ts#L27
• Accidental console.log in a ts server plugin will not crash the process (this currently happens if any non-json content is written to stdout)
• This would align the desktop TS Server more with the web version

[mjbvz]

I have work in progress that makes this change on the VS Code side and on the TS side (although I'll need help finalizing the TS part of this)

Unfortunately we'll likely need to keep support for the exiting rpc mechanism for any older clients that upgrade to use the new TypeScript version

[mjbvz]

VS Code PR: microsoft/vscode#135341

TS PR: #46418

[mjbvz]

This would also fix:

• Investigate compressing TS Server socket communication  #43156
• JS/TS protocol buffer hangs onto a lot of memory if on big request or response is used.  vscode#85565

@DanielRosenwasser Let's talk about this for 4.6

[mjbvz]

Not sure if this matters too much, but I believe switching to ipc would also let us easily transfer some data as binary. The obvious candidate is encodedSemanticClassifications-full, which currently returns a big array of numbers. This could be a Uint32Array instead