skip two test_gdb tests that fail when compiled in profile-opt mode:

StackNavigationTests.test_up_at_top and PyBtTests.test_threads.

Unfortunately we have no way of identifying if we were compiled profile-opt
or not from what is in sysconfig.get_config_vars() so we just disable it for
all optimized builds.  This test suite crazy fragile.

Lib/test/test_gdb.py

@@ -717,6 +717,8 @@ $''')
                             'Unable to find a newer python frame\n')
 
     @unittest.skipUnless(HAS_PYUP_PYDOWN, "test requires py-up/py-down commands")
+    @unittest.skipIf(python_is_optimized(),
+                     "Python was compiled with optimizations")
     def test_up_at_top(self):
         'Verify handling of "py-up" at the top of the stack'
         bt = self.get_stack_trace(script=self.get_sample_script(),
@@ -777,6 +779,8 @@ Traceback \(most recent call first\):
 
     @unittest.skipUnless(thread,
                          "Python was compiled without thread support")
+    @unittest.skipIf(python_is_optimized(),
+                     "Python was compiled with optimizations")
     def test_threads(self):
         'Verify that "py-bt" indicates threads that are waiting for the GIL'
         cmd = '''