replace loadgen

[turadg]

Problem to be solved

This repo has a number of open issues and we haven't prioritized fixing them because we expect to replace this tool with one or more others.

Draft design

needs work

• How will we test multi-node chain?
• How will we test state-sync?

[mhofman]

The deployment-test of agoric-sdk also has some customization meant to trigger more aggressively any execution divergence: it compiles xsnap with XSNAP_RANDOM_INIT which causes uninitialized memory in xsnap to not be zero filled. That results in diverging heap snapshots if there is any uninitialized memory. It's possible a more dedicated test could be used instead.