seastar-addr2line: relax the backtrace matching
seastar-addr2line: relax the backtrace matching

Allow an arbitrary prefix on the line containing an address as the last
word. This allows for piping journalctl output through seastar-addr2line
as journalctl entries have a date and time as well as other stuff as a
prefix on each line.

avikivity/seastar,avikivity/seastar,scylladb/seastar,cloudius-systems/seastar,dreamsxin/seastar,syuu1228/seastar,dreamsxin/seastar,dreamsxin/seastar,cloudius-systems/seastar,avikivity/seastar,scylladb/seastar,cloudius-systems/seastar,scylladb/seastar,syuu1228/seastar,syuu1228/seastar