Invalid PER (aligned) encoding of INTEGER (0..65535)

When using the aligned version of the native PER codec, an INTEGER type constrained to exactly 64K values is encoded as if it was unconstrained (referred to as 'the indefinite length case' in the PER standard). Only integers with more than 64K possible values are supposed to be encoded this way. Integers with exactly 64K values are supposed to be encoded on two octets ('the two-octet case').

/cc @aknappqwt @mmagyari