A Cflow binding represents an extracted cflow or cflowbelow subexpression
For a given pointcut "pcA and cflowA or cflowbelowB", we will extract two bindings.
The m_cflowID must be unique on a per cflow sub expresion basis ie JVM wide.
Note: CflowBinding hashcode depends on Cflow_ID (sub expr) + isCflowBelow only.