[kernel|erts] Fixed offset [add|drop]_membership bug offset bug
[kernel|erts] Fixed offset [add|drop]_membership bug offset bug

Offset bug while processing add_membership and drop_membership
options causing options after in the options list to be invalid
and therefor not processed properly.

OTP-18323

erlang/otp,erlang/otp,bjorng/otp,erlang/otp,erlang/otp,bjorng/otp,erlang/otp,bjorng/otp,bjorng/otp,bjorng/otp,bjorng/otp,erlang/otp,erlang/otp,bjorng/otp,bjorng/otp,erlang/otp,bjorng/otp,erlang/otp,erlang/otp,bjorng/otp