Revert "Added basic unit test for llvm-cov."

This reverts commit r194451.

Not sure why the tests are failing on the buildbot. They run fine on my
local machine. Could it possibly be because of the endianness of the
architectures? The GCNO and GCDA files are little-endian encoded, and
llvm-cov expects it to remain that way. Is this a safe assumption?

llvm-svn: 194454