Integer32 and UInteger32 loops can be much slower than Integer

Loops using Integer32 or UInteger32 counters have been reported to run substantially more slowly than equivalent Integer loops on the VM backend, including after warm-up. Investigate the difference and reduce avoidable overhead while preserving the types' existing arithmetic, conversion and loop behaviour.

The report also measures slower construction of arrays containing the 32-bit types. Investigate counter overhead and element conversion separately so any improvement addresses the measured workload.