Add last year's klee made to work on Ubuntu 22.04

Basically I added clang-9 and llvm-link-9 into the bin folder and changed bin/klee to use these versions that we now ship along the tool instead of the OS ones. The reason is we now use Ubuntu 22.04 for the competition and there is no clang-9 there anymore. These two binaries also needed 3 shared libaries that are also not available on Ubuntu22.04. I added them to bin/lib/ and used the LD_PRELOAD trick to make clang-9 and llvm-link-9 use these libraries from that folder.

I documented the changes here (@dbeyer please make that repo public) https://gitlab.com/sosy-lab/software/klee-hors-concours