Does importprivkey add the wrong private key?

### Describe the issue
Does importprivkey add the wrong private key?

1. Generate a address through **getnewaddress**;
2. Dump a private key (**WIF**) for this address through **dumpprivkey** (valid correct WIF, **checked**);
3. Turn off Bitcoin ABC;
4. Rename **wallet.dat** to **wallet_dump.dat**;
5. Turn on Bitcoin ABC;
6. Import a private key (**WIF**) through **importprivkey**.

### Expected behaviour
Same private key imported. Same address added (generated).

### Actual behaviour
Another private key imported or another address added (generated).

### What version of bitcoin-abc are you using?
v0.19.6.0-610f36bf9

### Any extra information that might be useful in the debugging process.
https://github.com/Bitcoin-ABC/bitcoin-abc/issues/302

Start with the getnewaddress, dumpprivkey, and importprivkey RPC sequence described above, using wallet.dat and wallet_dump.dat to reproduce it on v0.19.6.0-610f36bf9. Compare the imported WIF and resulting address with the dumped key, and review linked issue #302 for related context. Done means the mismatch is reproduced and its behavior is narrowed to a specific wallet operation.

Written by the indexing model from the issue text.