- Moved regex init code outside search_probe function (avoiding to be
called again at every invocation)
- inlined search_probe function
- Added std::regex::optimize flag to regex
- Fixed search of "software*" and "hardware*"

Before:

time ./bpftrace -l '*xfs*'|wc -l
2363

real	0m1.841s
user	0m1.576s
sys	0m0.261s

After:

time ./bpftrace -l '*xfs*'|wc -l
2363

real	0m1.179s
user	0m0.904s
sys	0m0.271s