Skip TestMultithreaded.test_sb_api_listener_resume on linux

The test still fails occasionally (1/100 runs). Upgrade the xfail to
skip.

llvm-svn: 349487

lldb/packages/Python/lldbsuite/test/api/multithreaded/TestMultithreaded.py

@@ -68,7 +68,7 @@ class SBBreakpointCallbackCase(TestBase):
     # clang-cl does not support throw or catch (llvm.org/pr24538)
     @skipIfWindows
     @expectedFlakeyFreeBSD
-    @expectedFailureAll(oslist=["linux"])
+    @skipIf(oslist=["linux"]) # flakey
     def test_sb_api_listener_resume(self):
         """ Test that a process can be resumed from a non-main thread. """
         self.build_and_test(