testing/{clang14,llvm14}: move from main
The last aports in main/community that depended on llvm14 were rebuilt against llvm16, so we can decommission it now. However, there's one aport in testing that still depends on llvm14 - smlsharp.
The last aports in main/community that depended on llvm14 were rebuilt against llvm16, so we can decommission it now. However, there's one aport in testing that still depends on llvm14 - smlsharp.