Updated ObjectFileELF tests to include more varaints.

Removed the distribution EXEs from FreeBSD and Ubuntu.
Added a hello-world .cpp file, and compiled it for
several platform/compiler variants:

Ubuntu 14.04 x86_64, clang 3.5 (the ubuntu1 3.5 pre variant)
Ubuntu 14.04 x86_64, gcc 4.8.2
FreeBSD 10.0 x86_64, clang 3.3
FreeBSD 10.0 x86_64, gcc 4.7.3
NetBSD 6.1 x86_64, gcc 4.5.3

I also added the NetBSD expected architecture and triple.
Note I have NetBSD not appending the version info to the
OS name, in contrast to FreeBSD.

llvm-svn: 211954