[llvm-cov] Do not print out the filename of the object file

[llvm-cov] Do not print out the filename of the object file

When we load coverage data from multiple objects, we don't have a way to
attribute a source object to a function record. Printing out the object
filename next to the source filename is already not very useful: soon,
it'll actually become misleading. Stop printing out the filename now.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@285043 91177308-0d34-0410-b5e6-96231b3b80d8