bpo-15999: Clean up of handling boolean arguments. (GH-15610)

* Use the 'p' format unit instead of manually called PyObject_IsTrue().
* Pass boolean value instead 0/1 integers to functions that needs boolean.
* Convert some arguments to boolean only once.

Lib/doctest.py

@@ -1326,7 +1326,7 @@ class DocTestRunner:
             try:
                 # Don't blink!  This is where the user's code gets run.
                 exec(compile(example.source, filename, "single",
-                             compileflags, 1), test.globs)
+                             compileflags, True), test.globs)
                 self.debugger.set_continue() # ==== Example Finished ====
                 exception = None
             except KeyboardInterrupt: