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

[Kazu Hirata via cfe-commits]

kazutakahirata 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!


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