String operations leaking in 0.11.0

[karllessard]

Hi, using 0.11.0 release code, I'm observing a memory leak that is happening when using the following operations from the onnxruntime extensions:

StringEqual, StringToHashBucketFast, StringJoin

When running a benchmark of 30K inference/second, the leak appears quite obviously. Removing these operations from our graph stops the leak. Also if I downgrade to 0.10.0, the issue seems to be resolved.

I don't think it matters but I'm using the Java client 1.16.3 of the onnxruntime.