Generate nuw GEPs for struct member accesses, as inbounds + non-negative
implies nuw.
Regression tests are updated using update scripts where possible, and by
find + replace where not.
functions in getter/setter functions of non-trivial C struct properties
This fixes a bug where the getter/setter functions were doing a trivial
copy instead of calling the synthesized functions that copy non-trivial
C struct types.
This fixes https://github.com/llvm/llvm-project/issues/56680.
Differential Revision: https://reviews.llvm.org/D131701
