don't fail when (expected) error output is produced. This fixes 17 tests.
While I was there, I also made all RUN lines of the form "not llvm-as..." a bit
more consistent, they now all redirect stderr and stdout to /dev/null and use
input redirect to read their input.
llvm-svn: 52174
global variables that needed to be passed in. This makes it possible to
add new global variables with only a couple changes (Makefile and llvm-dg.exp)
instead of touching every single dg.exp file.
llvm-svn: 35918
