gh-91731: Replace Py_BUILD_ASSERT() with static_assert() (#91730)

Python 3.11 now uses C11 standard which adds static_assert()
to <assert.h>.

* In pytime.c, replace Py_BUILD_ASSERT() with preprocessor checks on
  SIZEOF_TIME_T with #error.
* On macOS, py_mach_timebase_info() now accepts timebase members with
  the same size than _PyTime_t.
* py_get_monotonic_clock() now saturates GetTickCount64() to
  _PyTime_MAX: GetTickCount64() is unsigned, whereas _PyTime_t is
  signed.