Revert "Fixup XFAIL marking on TestConstVariables for clang version"

[chaoren]

Summary

Linux with ToT clang (3.8) fails.

This reverts commit r247633.

test/lang/c/const_variables/TestConstVariables.py

class ConstVariableTestCase(TestBase):
     mydir = TestBase.compute_mydir(__file__)
 
     @dsym_test
     def test_with_dsym_and_run_command(self):
         """Test interpreted and JITted expressions on constant values."""
         self.buildDsym()
         self.const_variable()
 
-    @expectedFailureAll(
-        oslist=["freebsd", "linux"], compiler="clang",
-        compiler_version=['<', '3.6'])
+    @expectedFailureAll(oslist=["freebsd", "linux"], compiler="clang")
     @expectedFailureAll(oslist=["freebsd", "linux"], compiler="icc")
     @expectedFailureWindows("llvm.org/pr24489: Name lookup not working correctly on Windows")
     @expectedFailureWindows("llvm.org/pr24490: We shouldn't be using platform-specific names like `getpid` in tests")
     @dwarf_test
     def test_with_dwarf_and_run_command(self):
         """Test interpreted and JITted expressions on constant values."""
         self.buildDwarf()
         self.const_variable()