[clang] [clang][ASTImporter] Only reorder fields of RecordDecls (PR #77079)

[Michael Buch via cfe-commits]

Michael137 wrote:

Tried to find a way to test "objective-c fields aren't reordered". After talking to some objective-c experts, there doesn't seem to be a good way to force such "incorrect field order", because it's strictly an in-order language. Reducing the LLDB crashes has been tricky because the reproducers require a somewhat complex setup. @balazske If you're ok with it, I'll go ahead and merge it like this, given it's essentially a minor revert.

Separately I'll try to see if I can simplify the LLDB reproducer, but that'll take some time

https://github.com/llvm/llvm-project/pull/77079