'agoric start local-chain' needs RUN

[warner]

Describe the bug

When setting up the load generator for the phase3 testnet, @michaelfig and I realized that the new "bank/virtual purse" setup had not been updated sufficiently to allow the agoric start local-chain / agoric start local-solo approach to grant an initial allocation of RUN and BLD to the newly provisioned client. To overcome this, I had to switch to using the packages/cosmic-swingset Makefile and run the "scenario2" setup tools therein.

To simplify the #3107 daily perf test, I'd like to return to using agoric start instead of fussing about with the cosmic-swingset internals. I think @michaelfig said this wouldn't be too hard to fix, but we put it off in the time pressure of that testnet setup.

So the task is to do whatever updates are needed to allow agoric start local-chain / agoric start local-solo to get the same initial balances of RUN and BLD that clients get on the real testnet.

cc @mhofman I think some portions of your perf test will depend upon this: the "faucet" task should work fine, and we should start there, but if/when we want to enable the AMM or Vault tasks, we'll need a pre-allocated supply of tokens to work with.