test: speed up wallet_fundrawtransaction.py and wallet_sendall.py

test/functional/wallet_fundrawtransaction.py

@@ -983,6 +983,8 @@ class RawTransactionsTest(BitcoinTestFramework):
         # are selected, the transaction will end up being too large, so it
         # shouldn't use BnB and instead fall back to Knapsack but that behavior
         # is not implemented yet. For now we just check that we get an error.
+        # First, force the wallet to bulk-generate the addresses we'll need.
+        recipient.keypoolrefill(1500)
         for _ in range(1500):
             outputs[recipient.getnewaddress()] = 0.1
         wallet.sendmany("", outputs)

test/functional/wallet_sendall.py

@@ -320,6 +320,10 @@ class SendallTest(BitcoinTestFramework):
     # This tests needs to be the last one otherwise @cleanup will fail with "Transaction too large" error
     def sendall_fails_with_transaction_too_large(self):
         self.log.info("Test that sendall fails if resulting transaction is too large")
+
+        # Force the wallet to bulk-generate the addresses we'll need
+        self.wallet.keypoolrefill(1600)
+
         # create many inputs
         outputs = {self.wallet.getnewaddress(): 0.000025 for _ in range(1600)}
         self.def_wallet.sendmany(amounts=outputs)