_hotshot hotshot_profiler(): If write_header() returned

an error code, this let `self` leak.  This is a disaster
on Windows, since `self` already points to a newly-opened
file object, and it was impossible for Python code to
close the thing since the only reference to it was in a
blob of leaked C memory.

test_hotshot test_bad_sys_path():  This new test provoked
the C bug above.  This test passed, but left an open
"@test" file behind, which caused a massive cascade of
bogus test failures in later, unrelated tests on Windows.
Changed the test code to remove the @test file it leaves
behind, which relies on the change above to close that
file first.

Modules/_hotshot.c

@@ -1525,9 +1525,11 @@ hotshot_profiler(PyObject *unused, PyObject *args)
             calibrate();
             calibrate();
         }
-        if (write_header(self))
+        if (write_header(self)) {
             /* some error occurred, exception has been set */
+            Py_DECREF(self);
             self = NULL;
+        }
     }
     return (PyObject *) self;
 }