77efd6800c
rustc_trans: approximate ABI alignment for padding/union fillers. Before #45225 and after this PR, unions and enums are filled with integers of size and alignment matching their alignment (e.g. `Option<u32>` becomes `[u32; 2]`) instead of mere bytes. Also, the alignment padding between struct fields gets this treatment after this PR. Partially helps with some reduced testcases in #46449, although it doesn't solve the bug itself.