test: Replace importprivkey with wallet_importprivkey

importprivkey was a legacy wallet only RPC which had a helper for
descriptor wallets in tests. Add wallet_importprivkey helper and use it
wherever importprivkey is used (other than backward compatibility tests)

test/functional/test_framework/test_framework.py

@@ -35,6 +35,7 @@ from .util import (
     initialize_datadir,
     p2p_port,
     wait_until_helper_internal,
+    wallet_importprivkey,
 )
 
 
@@ -485,7 +486,7 @@ class BitcoinTestFramework(metaclass=BitcoinTestMetaClass):
             n = self.nodes[node]
             if wallet_name is not None:
                 n.createwallet(wallet_name=wallet_name, load_on_startup=True)
-            n.importprivkey(privkey=n.get_deterministic_priv_key().key, label='coinbase', rescan=True)
+            wallet_importprivkey(n.get_wallet_rpc(wallet_name), n.get_deterministic_priv_key().key, 0, label="coinbase")
 
     def run_test(self):
         """Tests must override this method to define test logic"""