[clang] Fix false negative when value initializing a field annotated with [[clang::require_field_initialization]] (PR #124329)

[via cfe-commits]

higher-performance wrote:

Note the build error appears unrelated:

```
# | /var/lib/buildkite-agent/builds/linux-56-59b8f5d88-gwhg7-1/llvm-project/github-pull-requests/build-runtimes/libcxxabi/test-suite-install/include/c++/v1/__chrono/utc_clock.h:94:11: error: unknown type name 'tzdb'
# |    94 |     const tzdb& __tzdb = chrono::get_tzdb();
# |       |           ^
```

https://github.com/llvm/llvm-project/pull/124329