Make this test an expected fail on darwin until we can fix this bug.

llvm-svn: 197087

lldb/test/expression_command/radar_9673664/TestExprHelpExamples.py

@@ -19,7 +19,7 @@ class Radar9673644TestCase(TestBase):
         self.main_source = "main.c"
         self.line = line_number(self.main_source, '// Set breakpoint here.')
 
-    # rdar://problem/9673664
+    @expectedFailureDarwin(15641319)
     def test_expr_commands(self):
         """The following expression commands should just work."""
         self.buildDefault()