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/wallet_importprunedfunds.py

@@ -15,6 +15,7 @@ from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import (
     assert_equal,
     assert_raises_rpc_error,
+    wallet_importprivkey,
 )
 from test_framework.wallet_util import generate_keypair
 
@@ -38,7 +39,7 @@ class ImportPrunedFundsTest(BitcoinTestFramework):
         # privkey
         address3_privkey, address3_pubkey = generate_keypair(wif=True)
         address3 = key_to_p2wpkh(address3_pubkey)
-        self.nodes[0].importprivkey(address3_privkey)
+        wallet_importprivkey(self.nodes[0], address3_privkey, "now")
 
         # Check only one address
         address_info = self.nodes[0].getaddressinfo(address1)
@@ -95,7 +96,7 @@ class ImportPrunedFundsTest(BitcoinTestFramework):
 
         # Import with private key with no rescan
         w1 = self.nodes[1].get_wallet_rpc(self.default_wallet_name)
-        w1.importprivkey(privkey=address3_privkey, rescan=False)
+        wallet_importprivkey(w1, address3_privkey, "now")
         w1.importprunedfunds(rawtxn3, proof3)
         assert [tx for tx in w1.listtransactions() if tx['txid'] == txnid3]
         balance3 = w1.getbalance()