Remove all the internal members of the union. Instead replace
it with raw storage (uchar[]) aligned to max_align_t.
Place all accesses to the internal members with get<> methods
for consistency.
Change-Id: Icebf46b90c9375aa6ea0b5913b2132608e8c223d
Reviewed-by: Maurice Kalinowski <maurice.kalinowski@qt.io>