Fix linux fallout from c++ gmodules enable

TestLibcxxListLoop - fails because the evil "define private public"
  trick does not work with gmodules. The purpose of the test is not to
  test debug info parsing so I just mark it as no_debug_info_testcase.
  In the long term it may be interesting to write a mock std::list which
  will allow us to test bad inputs to data formatters more easily.
TestGModules - seems to be a genuine bug. Filed pr36107 and xfailed.

llvm-svn: 323520