IR: support setDebugSafety builtin function

src/codegen.cpp

@@ -1681,6 +1681,7 @@ static LLVMValueRef ir_render_instruction(CodeGen *g, IrExecutable *executable,
         case IrInstructionIdPtrTypeChild:
         case IrInstructionIdFieldPtr:
         case IrInstructionIdSetFnTest:
+        case IrInstructionIdSetDebugSafety:
         case IrInstructionIdArrayType:
         case IrInstructionIdSliceType:
             zig_unreachable();