test: bring back old (sync subtensor) tests and fix them

bittensor/core/extrinsics/registration.py

@@ -11,12 +11,12 @@
 
 from bittensor.utils import unlock_key
 from bittensor.utils.btlogging import logging
-from bittensor.utils.registration import log_no_torch_error, torch
+from bittensor.utils.registration import create_pow, log_no_torch_error, torch
 
 if TYPE_CHECKING:
     from bittensor_wallet import Wallet
     from bittensor.core.subtensor import Subtensor
-    from bittensor.utils.registration.pow import POWSolution, create_pow
+    from bittensor.utils.registration.pow import POWSolution
 
 
 def _do_burned_register(

bittensor/core/extrinsics/staking.py

@@ -93,8 +93,10 @@ def _check_threshold_amount(
     if amount is None:
         # Stake it all.
         staking_balance = Balance.from_tao(old_balance.tao)
+    elif not isinstance(amount, Balance):
+        staking_balance = Balance.from_tao(amount)
     else:
-        staking_balance = Balance.from_tao(amount.tao)
+        staking_balance = amount
 
     # Leave existential balance to keep key alive.
     if staking_balance > old_balance - existential_deposit: