Drop redundant formal parameter from TAKE1_UL1_RET2

This fixes the actual cause for #8661, i.e. a mismatch between the
actual arity of the Cmm implementation and the arity declared in the
foreign import statement.

This also reverts [a3878d17/integer-gmp] as the workaround isn't needed
anymore.

Signed-off-by: Herbert Valerio Riedel <hvr@gnu.org>