[testsuite] Add retries to test_startup_sync_state
[testsuite] Add retries to test_startup_sync_state

\# Summary

test_startup_sync_state was flaky probably because we were
not waiting for sync to complete.

This adds logic to retry and verify that the balances that
we expect are the actual balances in the wallet

\#Test Plan

Test succeeds locally

Closes: #1349
Approved by: ankushagarwal

aptos-labs/aptos-core,aptos-labs/aptos-core,aptos-labs/aptos-core,libra/libra,aptos-labs/aptos-core,libra/libra,aptos-labs/aptos-core,libra/libra,libra/libra,aptos-labs/aptos-core,libra/libra,aptos-labs/aptos-core