Add spec for non-local return bubbling through lambda.

Add for #3143.

spec/ruby/language/return_spec.rb

@@ -200,6 +200,21 @@ def f()
       ScratchPad.recorded.should == :before_return
     end
 
+    # jruby/jruby#3143
+    describe "downstream from a lambda" do
+      it "returns to its own return-capturing lexical enclosure" do
+        def a
+          ->{ yield }.call
+          return 2
+        end
+        def b
+          a { return 1 }
+        end
+
+        b.should == 1
+      end
+    end
+
   end
 
   describe "within two blocks" do