Revert "[mlir] Silence -Wdangling-assignment-gsl in OperationSupport.h (

llvm#126140)"

This reverts commit f6556af.

Buildbots are broken.

mlir/include/mlir/IR/OperationSupport.h

@@ -997,21 +997,13 @@ struct OperationState {
     if (!properties) {
       T *p = new T{};
       properties = p;
-#if defined(__clang__) && __has_warning("-Wdangling-assignment-gsl")
-#pragma clang diagnostic push
-// https://github.com/llvm/llvm-project/issues/126600
-#pragma clang diagnostic ignored "-Wdangling-assignment-gsl"
-#endif
       propertiesDeleter = [](OpaqueProperties prop) {
         delete prop.as<const T *>();
       };
-      propertiesSetter = [](OpaqueProperties newProp,
+      propertiesSetter = [](OpaqueProperties new_prop,
                             const OpaqueProperties prop) {
-        *newProp.as<T *>() = *prop.as<const T *>();
+        *new_prop.as<T *>() = *prop.as<const T *>();
       };
-#if defined(__clang__) && __has_warning("-Wdangling-assignment-gsl")
-#pragma clang diagnostic pop
-#endif
       propertiesId = TypeID::get<T>();
     }
     assert(propertiesId == TypeID::get<T>() && "Inconsistent properties");