Update pure concolict execution script

[lekcyjna123]

Hi, here is a bunch of changes to pure_concolic_execution.sh script.

• Fixed error which cause that no execution have been done if the binary was in the same directory and path was without a prefix ./ e.g: pure_concolic_execution.sh -i input a.out
• Fixed error which could cause a infinity loop. There was no check if the next input data have been already analysed. So there was possibility than in case when two inputs were allowed, then the first always generated the second, and the second the first.
• Added -f flag to allow automatic sorting out interesting (e.g. failing) files to separate directory.

[aurelf]

Thanks for the PR, it would be nice to have checks for this script in the gh actions. But for now the changes seem minor and so should be fine.