We also add Orchard-specific information to several RPCs in order for
tests to pass:
- `z_listunifiedreceivers`
- `z_getbalanceforaccount`
- `z_getbalanceforviewingkey`
We now use the empty array of pools to indicate that the default pools
should be used when providing a diversifier index parameter, instead of
needing a default sentinel value for the diversifier index parameter
(which was previously suggested as '*' which would have caused issues
for defining a consistent type for that parameter).
Jack Grigg
Kris Nuttycombe