Remove the (incorrect) forced alignment of the content of vector.

This was the 'right' thing to do for Emulated class (due to a deficiency in TStreamerInfo::ComputeSize)
but wrong from loaded classes (where TClass::Size() is authoritative for use in vector).

Which this change we should be back to the emulated vector and a compiled vector being bitwise
identical.

Note the forced alginment was introduced in 9968d0f0
to more properly support emulated class (which is more comprehensively done by fixing TStreamerInfo::ComputeSize)