Change Details

`make check` `test_runner.py` manual testing to be done: [x] migration from existing txindex (on testnet: 2 minute block on startup) [x] fresh txindex=1 with new code (testnet: 30 minutes background job) [ ] mainnet test [ ] test ElectrumX compatibility

`make check` `test_runner.py` manual testing to be done: [x] migration from existing txindex (on testnet: 2 minute block on startup) [x] fresh txindex=1 with new code (testnet: 30 minutes background job) [x] mainnet test (57 minutes for blocking migration on startup; 8.5 hours fresh indexing in background) [ ] test ElectrumX compatibility

`make check` `test_runner.py` manual testing to be done: [x] migration from existing txindex (on testnet: 2 minute block on startup) [x] fresh txindex=1 with new code (testnet: 30 minutes background job) [x] mainnet test (57 minutes for blocking migration on startup; ] mainnet test8.5 hours fresh indexing in background) [ ] test ElectrumX compatibility