A customer reported a case where addr2line was very slow. We tracked
this down to some N^2 behavior in _bfd_dwarf2_find_symbol_bias in the
unusual case where no function can be found.
This patch fixes the bug, and reduces the runtime for a particular
request from 127 seconds to 1 second.
bfd/ChangeLog
2019-08-19 Tom Tromey <tromey@adacore.com>