Make MuFast reentrant (ver2)

This is to make MuFastSteering reentrant motivated by ATR-21908 . The conventional design of RpcPatFinder tool in TrigL2MuonSA was called from a few different places but needs some variables across different calls to the tool. Based on advice from @smh , the variables used by the RpcPatFinder are changed to be local variables, and then passed to each function that needs them. @atlasbot