Previously, the tests assumed that the alignment of int and long equals
their size. This commit fixes the tests for targets like m68k that have
sizeof(int) == 4 and alignof(int) == 2. A static helper function sizemax
was introduced as the offset of the second element in Pair<int,long>
might be either determined by its alignment requirement or the size of
the preceding int element and we use the helper function to pick the
larger of the two values.