Deploy snowflake-server performance improvements 2022-09-23

The background is greatly increased usage and resulting load on the server in the past 2 days.

• [anti-censorship-team] Need to increase number of tor instances on snowflake-01 bridge, increased usage since yesterday
• #40173 (closed)
• #40086 (comment 2836854)

snowflake-server is remaining functional, but restarting every few hours due to out-of-memory conditions. I did some profiling yesterday and found a few optimizations. They may help, or they may not.

dcf/snowflake@03b2b56f...c2f7003e

The plan is to first deploy the optimizations with profiling enabled, for a few hours, to collect profiles under load. Then re-deploy without profiling, later today if nothing goes wrong.

/cc @linus