Skip part of test added in r331592 to help debug bot failures

Trying to debug why/where a few bots getting exit code 256 e.g.
http://green.lab.llvm.org/green/job/clang-stage1-cmake-RA-incremental/48471/testReport/Clang/CodeGen/thinlto_diagnostic_handler_remarks_with_hotness_ll/

and a few windows bots getting no output from that RUN line e.g.
http://lab.llvm.org:8011/builders/clang-x86-windows-msvc2015/builds/11865/steps/ninja%20check%201/logs/FAIL%3A%20Clang%3A%3Athinlto-diagnostic-handler-remarks-with-hotness.ll

llvm-svn: 331596