Enrich TS Server Tracepoints

[DanielRosenwasser]

Today a trace point in TS Server exists, but is not practically useful. In tsc traces, we dump a list of all the types, but that allows us to point at the type and say "this is the slow type"; however, types aren't stable between checks in the language service, so the same technique doesn't work.

We want to find a way to provide some extra information in TS Server trace points so that analyses can quickly point out what's going wrong.

[amcasey]

This was tracking an effort to collect server traces from users and enhance tracing until they were sufficient for diagnosing problems. In practice, we collected very few server traces. We probably want to close this and file a new issue when we have a plan.