[clang] [AST] Make nullability attributed-type construction const (PR #215756)

[via cfe-commits]

StoeckOverflow wrote:

The Linux CI failure looks unrelated to the patch. The only failure is an LLDB-DAP timeout in `lldb-api :: tools/lldb-dap/stackTraceMissingModule/TestDAP_stackTraceMissingModule.py` timing out during `disconnect`.

Could someone with permission rerun the failed Linux job?

https://github.com/llvm/llvm-project/pull/215756