offcputime: change user/kernel stack order
offcputime: change user/kernel stack order

see #559

shodoco/bcc,mcaleavya/bcc,tuxology/bcc,mkacik/bcc,mkacik/bcc,shodoco/bcc,mcaleavya/bcc,shodoco/bcc,mkacik/bcc,mcaleavya/bcc,shodoco/bcc,iovisor/bcc,romain-intel/bcc,brendangregg/bcc,iovisor/bcc,shodoco/bcc,romain-intel/bcc,romain-intel/bcc,iovisor/bcc,brendangregg/bcc,tuxology/bcc,romain-intel/bcc,iovisor/bcc,romain-intel/bcc,brendangregg/bcc,tuxology/bcc,brendangregg/bcc,brendangregg/bcc,mkacik/bcc,mcaleavya/bcc,mkacik/bcc,iovisor/bcc,tuxology/bcc,tuxology/bcc,mcaleavya/bcc