Message 293483 - Python tracker

-    @unittest.skipUnless(sysconfig.is_python_build(),
-                         'test.bat script is not installed')

I had to remove this decorator from test_tools_buildbot_test() since sysconfig.is_python_build() is false on Python 2.7 built with VS 2008 my Windows VM, whereas I didn't install Python!? I don't know why.

Moreover, the decorator was missing on test_pcbuild_rt(), likely a mistake in the backport from master.