* Fixed some reference leaks.
* Fixed a few reference leaks.
* Fixed a few more memory errors.
* Fixed a few more reference leaks.
* Revert minimal_test.py.
* Re-enable limited API.
* Removed some debugging and spurious changes.
* Addressed PR comments.
There was a bug in our arena code where we assumed that
sizeof(upb_array) would be a multiple of 8. On i386 it was
not, and this was causing memory corruption on 32-bit builds.