[Bug #19533] Add spec of infinite range inclusion

spec/ruby/core/range/case_compare_spec.rb

@@ -10,4 +10,10 @@ describe "Range#===" do
 
   it_behaves_like :range_cover_and_include, :===
   it_behaves_like :range_cover, :===
+
+  ruby_bug "#19533", "3.2"..."3.3" do
+    it "returns true on any value if begin and end are both nil" do
+      (nil..nil).should === 1
+    end
+  end
 end