jqueue: Update worker thread name to include opcode summary

With this patch, the worker thread name is updated to include a short
summary of the opcode (basically its OP_ID). The base name of job queue
threads is shortened from “JobQueue” to “Jq”. Logs and the lock monitor
will show a job verifying the cluster as e.g. “Jq2/Job1742/C_VERIFY”.

Signed-off-by: Michael Hanselmann <hansmi@google.com>
Reviewed-by: Iustin Pop <iustin@google.com>