hardening-check: Add support for detecting binaries compiled with -fstack-clash-protection

In reponse to https://bugs.launchpad.net/ubuntu/+source/devscripts/+bug/1820798/comments/10

This contains that original change plus a bunch of others to make perltidy happy and to NOT consider a failure to find -fstack-clash-protection instructions as bad since only binaries which do dynamic memory allocations on the stack (via alloca() or variable length arrays) will contain stack clash protections.