test: log sanity check assertion failures

test/functional/interface_usdt_utxocache.py

@@ -353,8 +353,12 @@ class UTXOCacheTracepointTest(BitcoinTestFramework):
                 "size": event.size
             })
             # sanity checks only
+            try:
                 assert event.memory > 0
                 assert event.duration > 0
+            except AssertionError:
+                self.log.exception("Assertion error")
+            else:
                 handle_flush_succeeds += 1
 
         bpf["utxocache_flush"].open_perf_buffer(handle_utxocache_flush)