Revert "Merge pull request #40356 from gmittert/TypeLayoutFixes"
This reverts commit d27e6e1e46a62c5f16d941a54c784d0fb510a94b, reversing
changes made to f2e85a2b1f7b67f315c1695b792c60330cf0bad5.
It causes an execution time failure in
`Interpreter/struct_extra_inhabitants.swift` with
```
ninja -C swift-macosx-x86_64 check-swift-optimize
```
rdar://86054209
