[clang] [clang][Modules] Fix the Size of `RecordDecl`'s `BitCodeAbbrevOp` (PR #133500)

[Qiongsi Wu via cfe-commits]

qiongsiwu wrote:

Note to reviewers:

A test case is added by https://github.com/swiftlang/llvm-project/pull/10371. This is difficult to test in the community llvm code base because the failure was discovered when building structs with `__ptrauth`, which is not available here. I tried a few things to simulate the situation but found it difficult. I am all ears if there are better ways to test this. 

https://github.com/llvm/llvm-project/pull/133500