HPCC-10525 Solve constant folding functions for ARM

ARM32 implementation - tested in isolation but not in the context of the
compiler, as I don't have a suitable machine.

Signed-off-by: Richard Chapman <rchapman@hpccsystems.com>
Stacks are normally aligned to 4, but public interfaces align to 8. Since this is a remote procedure call, I believe we should align to 8 anyway.