Modifications of fail_db.txt: ptr-22 fixed; runfails #20472; generic compfails 3.5->3.6

1. Removed ptr-22 test (the one with segfault) for knc from fail_db as it now successfully passes.
2. 12 runfails added (12 for clang and 12 for gcc) tracked in #20472. These should be fixed soon.
3. Added 26 compfails for generic-4 and 16 on llvm 3.6. These appeared in llvm 3.5 but were not investigated.

You can accept a partial pull request (without 2nd commit) if it turns out to be not convenient to ignore those runfails.