Auto merge of #149109 - scottmcm:align-always-alignment, r=tgross35

See if this is the time we can remove `layout::size_align`

This was a bad idea before, but now that `size_of` and `align_of` work completely differently than when removing it was first tried in 2020, maybe it makes sense now.

(Or maybe I'll just add another attempt to the list in the comments...)

r? ghost

Author: bors