listaddressgroupings returns an empty array

This issue tracker is only for technical issues related to bitcoin-abc.

General bitcoin questions and/or support requests and are best directed to the [Bitcoin StackExchange](https://bitcoin.stackexchange.com).

For reporting security issues, please contact people privately.

### Describe the issue

### Can you reliably reproduce the issue?
#### If so, please list the steps to reproduce below:
1. bitcoin-cli getnewaddress "payment"
2. bitcoin-cli listaddressgroupings
3.

### Expected behaviour
Tell us what should happen

[
[
[
"bchtest:qr6m2239fzcd23udrwe762xthjefqz7cugjtx7vq6p",
0.00000000,
"payment"
]
]
]

### Actual behaviour
Tell us what happens instead

[
]

### Screenshots.
If the issue is related to the GUI, screenshots can be added to this issue via drag & drop.

$ bitcoin-cli getnewaddress "payment"
bchtest:qr6m2239fzcd23udrwe762xthjefqz7cugjtx7vq6p
$ bitcoin-cli listaddressgroupings
[
]

### What version of bitcoin-abc are you using?
List the version number/commit ID, and if it is an official binary, self compiled or a distribution package such as PPA.

$ bitcoin-cli getinfo
{
"version": 180400,
"protocolversion": 70015,
"walletversion": 160300,
"balance": 0.00000000,
"blocks": 1266532,
"timeoffset": -1,
"connections": 10,
"proxy": "",
"difficulty": 2.857239689039206,
"testnet": true,
"keypoololdest": 1542261069,
"keypoolsize": 2000,
"paytxfee": 0.00000000,
"relayfee": 0.00001000,
"errors": ""
}

### Machine specs:
- OS: Ubuntu 16.04 LTS
- CPU:
- RAM:
- Disk size:
- Disk Type (HD/SDD):

### Any extra information that might be useful in the debugging process.
This is normally the contents of a `debug.log` or `config.log` file. Raw text or a link to a pastebin type site are preferred.