Get task information from control blocks

(1) The Prefix Save Area (PSA) points (->) to the CVT, which points to the SMCA, which gets us to the system name.

(2) PSATOLD -> JSCB -> SSIB -> jobtype, tasknum

(3) PSATOLD -> TIOT -> job, step, proc name plus allocated DD information

/*-------------------------------------------------------*/
/* Follow the control blocks to the Step Control Table.  */
/*-------------------------------------------------------*/
/* Psa                                  Prefix Save Area
/* Psa@540                              Pointer of PSATOLD
/* Psa@540=>tcb                         Task control block
/* Psa@540=>tcb+181                     Pointer of TCBJSCBB
/* Psa@540=>tcb+181=>jscb               JOBSTEP control block
/* Psa@540=>tcb+181=>jscb+261           Pointer to Job Control Table
/* Psa@540=>tcb+181=>jscb+261=>jct      Job Control Table
/* Psa@540=>tcb+181=>jscb+261=>jct+329  Pointer to Step Contolr Table
/* Psa@540=>tcb+181=>jscb+261=>jct+329=>sct Step Control Table*/
/*------------------------------------------------------------*/