Revert r196358: "llvm-cov: Added support for function checksums."

This currently breaks clang/test/CodeGen/code-coverage.c. The root cause
is that the newly introduced access to Funcs[j] is out of bounds.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@196365 91177308-0d34-0410-b5e6-96231b3b80d8