[MERGE] More than double the speed of "bzr selftest"

[Martin Pool]

Martin Pool has voted +1 (conditional).
Status is now: Conditionally approved
Comment:
Great subject!

You need to use bzrlib.osutils.rmtree to be safe on Windows.

+                    assert self.test_dir.endswith('/work'), 
self.test_dir
+                    shutil.rmtree(self.test_dir[:-len('/work')])

I think it would be cleaner and simpler to just do an addCleanup from 
TestCaseInTempDir.makeAndChdirToTestDir.  Wouldn't that work?

For details, see: 
http://bundlebuggy.aaronbentley.com/request/%3C20070411051823.GA20431%40steerpike.home.puzzling.org%3E