Fix interpreter path in in-repo interpreter test

The in-repo interpreters were moved from `third_party/cpython/lib` to
`third_party/cc/cpython` in #277, but the interpreter directory path in
`//test:interpreter_not_included_test` wasn't also updated, so the test
still passes even if please_pex erroneously packs the in-repo
interpreter into the .pex file. Update the path to fix the test.

Author: chrisnovakovic

test/interpreter_not_included_test.py

@@ -6,9 +6,9 @@
 class InterpreterNotIncludedTest(unittest.TestCase):
 
     def test_interpreter_is_not_included(self):
-        """Test that we don't include the interpreter as a tool."""
+        """Test that we don't include any in-repo interpreter in the .pex file."""
         zf = zipfile.ZipFile(sys.argv[0])
-        names = [name for name in zf.namelist() if "third_party/cpython/lib" in name]
+        names = [name for name in zf.namelist() if "third_party/cc/cpython/" in name]
         self.assertFalse(names)
 
     def test_arcat_is_not_included(self):