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>
I pushed a new version. Stack alignment is not quite the same thing as this ALIGNMENT value. Basically we need to align parameters by a minimum of 4 - but larger parameters require larger alignment (unlike on x86). And at the conclusion of the call, the stack needs to be 8-byte aligned (but you have to allow for the pushed PC in that calculation).