Exclude spec on 3.3 until it is fixed upstream

* See https://bugs.ruby-lang.org/issues/19427#note-15

Author: eregon

core/marshal/shared/load.rb

@@ -141,14 +141,16 @@
       end
 
       ruby_bug "#19427", "3.1"..."3.3" do
-        it "returns frozen object having #_dump method" do
-          object = Marshal.send(@method, Marshal.dump(UserDefined.new), freeze: true)
-          object.should.frozen?
-        end
+        ruby_bug "#19427", "3.1"..."3.4" do # https://bugs.ruby-lang.org/issues/19427#note-15
+          it "returns frozen object having #_dump method" do
+            object = Marshal.send(@method, Marshal.dump(UserDefined.new), freeze: true)
+            object.should.frozen?
+          end
 
-        it "returns frozen object responding to #marshal_dump and #marshal_load" do
-          object = Marshal.send(@method, Marshal.dump(UserMarshal.new), freeze: true)
-          object.should.frozen?
+          it "returns frozen object responding to #marshal_dump and #marshal_load" do
+            object = Marshal.send(@method, Marshal.dump(UserMarshal.new), freeze: true)
+            object.should.frozen?
+          end
         end
 
         it "returns frozen object extended by a module" do