Revert "Re #8882. Disable ubiquitous size_t conversion warning on 32 bit."

This reverts commit b80c5fd617542cfb7245076d107f6bbf823df7de.
No need for 32 bit specifics now that we no longer support it.
Re #8882. Remove code to handle 32 bit builds.

No longer needed as we're not supporting 32 bit going forward.