[clang] [CIR] Upstream initial support for complete record types (PR #135844)

[Erich Keane via cfe-commits]

https://github.com/erichkeane approved this pull request.

Still OK, see the request on line 46 of CIRGenRecordLayoutBuilder.cpp for the comment request previously mentioned.

https://github.com/llvm/llvm-project/pull/135844