test: Fix intermittent issue in wallet_import_rescan

test/functional/wallet_import_rescan.py

@@ -182,6 +182,7 @@ class ImportRescanTest(BitcoinTestFramework):
             self.nodes[0].generate(1)  # Generate one block for each send
             variant.confirmation_height = self.nodes[0].getblockcount()
             variant.timestamp = self.nodes[0].getblockheader(self.nodes[0].getbestblockhash())["time"]
+        self.sync_all() # Conclude sync before calling setmocktime to avoid timeouts
 
         # Generate a block further in the future (past the rescan window).
         assert_equal(self.nodes[0].getrawmempool(), [])