kallsyms_handler shouldn't rerun

[lucasduffey]

If kallsyms_handler finishes and the user saves the database - it shouldn't run when they open in a second time.

This doesn't seem to impact performance much - so low priority.

[lucasduffey]

This is blocking on core binary ninja feature

wait until binja developers persist session_data, then use a "kallsyms_analysed" flag to determine if kallsyms_handler should be run.