o Added a new feature to the test framework to skip long running tests conditionally.

  To not skip long running tests, pass '-l' to the test driver (dotest.py).

  An example:

    @unittest2.skipIf(TestBase.skipLongRunningTest(), "Skip this long running test")
    def test_foundation_disasm(self):
        ...

o Added a long running disassemble test to the foundation directory, which iterates
  the code symbols from Foundation.framework and kicks off a disassemble command for
  for the named function symbol.  Found a crasher: rdar://problem/8504895.

o Plus added/updated some comments for the TestBase class.

llvm-svn: 115368