899eb03926
Miscellaneous improvements to struct tail normalization 1. Make checks for foreign tails more accurate by normalizing the struct tail. I didn't write a test for this one. 2. Normalize when computing struct tail for `offset_of` for slice/str. This fixes the new solver only. 3. Normalizing when computing tails for disaligned reference check. This fixes both solvers. r? lcnr
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