[flang][NFC] Use tablegen to reduce MemoryAllocationOpt boilerplate (#90062)

This is another one that runs on functions but isn't appropriate to also
run on other top level operations. It needs to find all paths that
return from the function to free heap allocated memory. There isn't a
generic concept for general top level operations which is equivalent to
looking for function returns.

I removed the manual definition of the options structure because there
is already an identical definition in tablegen and the options are
documented in Passes.td.