[clang] [clang-tools-extra] [lldb] [clang] Remove intrusive reference count from `DiagnosticOptions` (PR #139584)

[Jan Svoboda via cfe-commits]

jansvoboda11 wrote:

> @jansvoboda11 I've revered your PR due buildbot failures above (and my local build failures with the same error messages). I'm happy to try your revised patch to see if it build cleanly. Thanks!

I already forward-fixed both failures: d25f95fdbc5314f30618912e18f00ad4dd720fa0 and b544853fc335bdba6edbcde33e0c284306cd08eb.

https://github.com/llvm/llvm-project/pull/139584