fix(acceptance): fix flakey psm test (#10747)

closes: #10728 

## Description

Using `-bblock` caused inconsistent timeout behavior due to txs not getting into a block on time. `psm.test.js` is observed to be the only test that sends transactions with `-bblock` set. In this PR we switch to the default option which is `sync`.

### Security Considerations

None.

### Scaling Considerations

Removing flakiness will help landing code faster.

### Documentation Considerations

None.

### Testing Considerations

Should force integration tests.

### Upgrade Considerations

`z:acceptance` runs after every upgrade.

a3p-integration/proposals/z:acceptance/psm.test.js

@@ -34,7 +34,6 @@ import {
   logRecord,
   maxMintBelowLimit,
   psmSwap,
-  sendOfferAgd,
 } from './test-lib/psm-lib.js';
 import { getBalances } from './test-lib/utils.js';
 
@@ -163,7 +162,7 @@ test.serial('swap into IST using agd with default gas', async t => {
       '--feePct',
       wantMintedFeeVal,
     ],
-    { ...psmSwapIo, sendOffer: sendOfferAgd },
+    psmSwapIo,
   );
 
   await checkSwapSucceeded(t, metricsBefore, balancesBefore, {

a3p-integration/proposals/z:acceptance/test-lib/psm-lib.js

@@ -434,6 +434,8 @@ export const initializeNewUser = async (name, fund, io) => {
 };
 
 /**
+ * UNTIL https://github.com/Agoric/agoric-sdk/issues/10746 better to use {@link sendOfferAgd}
+ *
  * Similar to
  * https://github.com/Agoric/agoric-3-proposals/blob/422b163fecfcf025d53431caebf6d476778b5db3/packages/synthetic-chain/src/lib/commonUpgradeHelpers.ts#L123-L139
  * However, for an address that is not provisioned, `agoric wallet send` is
@@ -478,7 +480,6 @@ export const sendOfferAgd = async (address, offerPromise) => {
       [`--keyring-backend=test`, `--from=${address}`],
       ['tx', 'swingset', 'wallet-action', '--allow-spend', offer],
       '--yes',
-      '-bblock',
       '-ojson',
     )
   );
@@ -522,7 +523,7 @@ export const sendOfferAgd = async (address, offerPromise) => {
  * }} io
  */
 export const psmSwap = async (address, params, io) => {
-  const { now, sendOffer = sendOfferAgoric, ...waitIO } = io;
+  const { now, sendOffer = sendOfferAgd, ...waitIO } = io;
   const offerId = `${address}-psm-swap-${now()}`;
   const newParams = ['psm', ...params, '--offerId', offerId];
   const offerPromise = executeCommand(agopsLocation, newParams);