Run Python 3.11 tests in CI

[hauntsaninja]

(Note that we mark these as success)

[hauntsaninja]

Looks like all the mypyc tests fail:

In file included from build/__native.c:11:
/home/runner/work/mypy/mypy/mypyc/lib-rt/exc_ops.c: In function ‘CPy_ExceptionMatches’:
/home/runner/work/mypy/mypy/mypyc/lib-rt/exc_ops.c:78:54: error: ‘_PyErr_StackItem’ {aka ‘struct _err_stackitem’} has no member named ‘exc_type’
   78 |     return PyErr_GivenExceptionMatches(CPy_ExcState()->exc_type, type);
      |                                                      ^~
/home/runner/work/mypy/mypy/mypyc/lib-rt/exc_ops.c: In function ‘CPy_AddTraceback’:
/home/runner/work/mypy/mypy/mypyc/lib-rt/exc_ops.c:217:14: error: dereferencing pointer to incomplete type ‘PyFrameObject’ {aka ‘struct _frame’}
  217 |     frame_obj->f_lineno = line;
      |              ^~
In file included from build/__native.c:12:
/home/runner/work/mypy/mypy/mypyc/lib-rt/misc_ops.c: In function ‘CPy_YieldFromErrorHandle’:
/home/runner/work/mypy/mypy/mypyc/lib-rt/misc_ops.c:48:40: error: ‘_PyErr_StackItem’ {aka ‘struct _err_stackitem’} has no member named ‘exc_type’
   48 |     PyObject *exc_type = CPy_ExcState()->exc_type;
      |                                        ^~
In file included from build/__native.c:11:
/home/runner/work/mypy/mypy/mypyc/lib-rt/exc_ops.c: In function ‘CPy_ExceptionMatches’:
/home/runner/work/mypy/mypy/mypyc/lib-rt/exc_ops.c:79:1: error: control reaches end of non-void function [-Werror=return-type]
   79 | }
      | ^
build/__native.c: At top level:
cc1: error: unrecognized command line option ‘-Wno-unknown-warning-option’ [-Werror]
cc1: error: unrecognized command line option ‘-Wno-unused-command-line-argument’ [-Werror]
cc1: all warnings being treated as errors

[github-actions]

According to mypy_primer, this change has no effect on the checked open source code. 🤖🎉