Fix Feature/Envp.c test for llvm-lit by providing the PWD environmental variable
in test environment.
Allow llvm-lit from 2.9 to work by hacking %T substitution variable.
Force python2 to be used when running llvm-lit. This needs to be fixed
properly at configure time at some point.
Fixed Feature/InAndOutOfBounds.c so it did not make use of ! which
seemed to causing problems for llvm-lit's parser.