* [3.5] bpo-32563: Get expat to compile under C89

expat: Add artificial scopes in xmltok.c utf8_toUtf8() to fix c89 compilation.

Cherry-picked from libexpat commit e0b290eb3d8f4c4b45137a7d7f4f8db812145bd2

* Backport XML RPC test skip to 3.5

The buildbot service upgrade removed the XML-RPC
interface, so this test no longer works (through no
fault of the standard library).

* Don't configure a nonexistent Python