[supervisor/code] grpc tracing and terminal fixes

[akosyakov]

What it does

• Allow to enable pprof and grpc tracing for some environments.
• fix [code] terminals stop working #3127:
  • bump up to latest Node.js 12 to pick up fixes for stale http2 streams hanging forever, see Request streams from http2 intermittantly not emitting end event nodejs/node#31309
  • add deadlines for all calls to supervisor
• fix Terminals aren't reconnected on Code reload #3461: don't shutdown terminals if listening failed because of internal grpc issues

Changes in VS Code: gitpod-io/openvscode-server#8

Additional env variables which were useful to investigate grpc over http2:

# enable @grpc/grpc-js tracing
export GRPC_NODE_VERBOSITY=DEBUG
export GRPC_NODE_TRACE=all

# enable node http2 tracing
export NODE_DEBUG=http2

How to test

• Start a workspace: https://ak-supervisor-debug-mode.staging.gitpod-dev.com/#https://github.com/gitpod-io/vscode
• check that pprof endpoint works by opening _supervisor/debug/pprof endpoint on a workspace origin
• check that workspace logs contain supervisor grpc tracing logs
• try to break terminals:
  • create new user terminals and reload the page
  • check that all task and user terminals are present on each reload and operatable

[geropl]

Reviewing...

[svenefftinge]

I started a workspace and created a bunch of terminals. They all worked and survived multiple reloads without any issues.
One thing I saw is that the width of the logs outputted before the IDE was visible were rendered narrowly (3 cols or so).

[geropl]

Works really nice.

[geropl]

Not sure if it's related and what's the trigger: Sometimes all terminals in one "row" get cramped to the right:

Maybe on vertical re-sizing...

[akosyakov]

I'm merging and will tackle terminal resize issues separately.

[akosyakov]

A follow up issue about terminal resize: #3553