message: xfail this test on all Linux platforms, it's been failing on x86_64 as well.
  <rdar://problem/30931804>
diff: @@ -27,6 +27,7 @@ class ThreadsStackTracesTestCase(TestBase):
  # We are unable to produce a backtrace of the main thread when the thread
  # is blocked in fgets
  @expectedFailureAll("llvm.org/pr23043", ["linux"], archs=["i386"])
  + @expectedFailureAll(bugnumber="<rdar://problem/30931804>", oslist=["linux"])
  # The __thread_start function in libc doesn't contain any epilogue and prologue instructions
  # hence unwinding fail when we are stopped in __thread_start
  @expectedFailureAll(triple='mips*')
  