[llvm-cov] Disable name-compression in a test binary

This should fix the lld bot:

The Buildbot has detected a new failure on builder llvm-clang-lld-x86_64-scei-ps4-ubuntu-fast while building cfe.
Full details are available at:
http://lab.llvm.org:8011/builders/llvm-clang-lld-x86_64-scei-ps4-ubuntu-fast/builds/16993

llvm-svn: 312821