Revert "Temporarily comment out these syntax tests"

This reverts commit 73c87e7.

test/mri/ruby/test_keyword.rb

@@ -182,12 +182,12 @@ def test_method_parameters
                   [:keyrest, :kw], [:block, :b]], method(:f9).parameters)
   end
 
-  # def test_keyword_with_anonymous_keyword_splat
-  #   def self.a(b: 1, **) [b, **] end
-  #   kw = {b: 2, c: 3}
-  #   assert_equal([2, {c: 3}], a(**kw))
-  #   assert_equal({b: 2, c: 3}, kw)
-  # end
+  def test_keyword_with_anonymous_keyword_splat
+    def self.a(b: 1, **) [b, **] end
+    kw = {b: 2, c: 3}
+    assert_equal([2, {c: 3}], a(**kw))
+    assert_equal({b: 2, c: 3}, kw)
+  end
 
   def test_keyword_splat_nil
     # cfunc call
@@ -2817,23 +2817,23 @@ class << o
     assert_raise(FrozenError) { c.send(:ruby2_keywords, :baz) }
   end
 
-  # def test_anon_splat_ruby2_keywords
-  #   singleton_class.class_exec do
-  #     def bar(*a, **kw)
-  #       [a, kw]
-  #     end
-  #
-  #     ruby2_keywords def bar_anon(*)
-  #       bar(*)
-  #     end
-  #   end
-  #
-  #   a = [1, 2]
-  #   kw = {a: 1}
-  #   assert_equal([[1, 2], {a: 1}], bar_anon(*a, **kw))
-  #   assert_equal([1, 2], a)
-  #   assert_equal({a: 1}, kw)
-  # end
+  def test_anon_splat_ruby2_keywords
+    singleton_class.class_exec do
+      def bar(*a, **kw)
+        [a, kw]
+      end
+
+      ruby2_keywords def bar_anon(*)
+        bar(*)
+      end
+    end
+
+    a = [1, 2]
+    kw = {a: 1}
+    assert_equal([[1, 2], {a: 1}], bar_anon(*a, **kw))
+    assert_equal([1, 2], a)
+    assert_equal({a: 1}, kw)
+  end
 
   def test_top_ruby2_keywords
     assert_in_out_err([], <<-INPUT, ["[1, 2, 3]", "{:k=>1}"], [])