provisionPool Error: keyword ... must be an ascii identifier starting with upper case

[dckc]

Describe the bug

NOTE: This bug is only critical for assets where we're adding a PSM. Otherwise, the provisionPool can't use them anyway.

Community testing with stATOM showed that the provisionPool will fail to track its balance of any asset registered in the vbank with an issuerName that doesn't match the Zoe keyword constraints: ASCII identifier string that must begin with an upper case letter.

To Reproduce

Steps to reproduce the behavior:

1. adapt the STARS proposal to stATOM
2. deploy bundles; make a governance proposal; vote
3. Error: keyword "stATOM" must be an ascii identifier starting with upper case shows in chain logs

The stack trace includes a call to saveIssuer.
https://github.com/Agoric/agoric-sdk/blob/mainnet1B/packages/vats/src/provisionPoolKit.js#L347

Expected behavior

Assets known as xyzABC work fine for funding the provisionPool via a PSM.

Platform Environment

mainnet1B code as well as a few other local chain configurations

Additional context

Community testing with stATOM with @0xpatrickdev

Logs / stacktrace

stack trace from a scenario2 local-chain log

2023-08-22T15:54:16.291Z SwingSet: xsnap: v29: Error: keyword "stATOM" must be an ascii identifier starting with upper case.
 at construct ()
 at Error (/bundled-source/.../node_modules/ses/src/error/tame-error-constructor.js:56)
 at makeError (/bundled-source/.../node_modules/ses/src/error/assert.js:273)
 at fail (/bundled-source/.../node_modules/ses/src/error/assert.js:387)
 at assertKeywordName (.../zoe/src/cleanProposal.js:33)
 at assertUniqueKeyword (.../zoe/src/instanceRecordStorage.js:106)
 at apply ()
 at apply ()
 at In "assertUniqueKeyword" method of (InstanceRecord) (/bundled-source/.../node_modules/@endo/exo/src/exo-tools.js:42)
 at saveIssuer (.../zoe/src/contractFacet/zcfZygote.js:261)
 at saveIssuer (.../zoe/src/contractFacet/zcfZygote.js:257)
 at updateState (.../vats/src/provisionPoolKit.js:344)
 at updateState (.../vats/src/provisionPoolKit.js:342)
 at (.../notifier/src/asyncIterableAdaptor.js:63)
 at ()