[PATCH] FFI: Fix pass small ints in foreign call wrappers

[PATCH] FFI: Fix pass small ints in foreign call wrappers

The Haskell calling convention requires integer parameters smaller
than wordsize to be promoted to wordsize (where the upper bits are
don't care). To access such small integer parameter read a word from
the parameter array and then cast that word to the small integer
target type.

Fixes #15933

Gbp-Pq: Name fix-big-endian-ffi