imports e.g. test_support must do so using an absolute package name
such as "import test.test_support" or "from test import test_support".
This also updates the README in Lib/test, and gets rid of the
duplicate data dirctory in Lib/test/data (replaced by
Lib/email/test/data).
Now Tim and Jack can have at it. :)
Also add a test that Python doesn't die with SIGXFSZ if it exceeds the
file rlimit. (Assuming this will also test the behavior when the 2GB
limit is exceed on a platform that doesn't have large file support.)