[Bug #19906] Add the test

Author: nobu

test/ruby/test_iseq.rb

@@ -781,4 +781,14 @@ def test_unreachable_pattern_matching
       end
     end;
   end
+
+  def test_loading_kwargs_memory_leak
+    assert_no_memory_leak([], "#{<<~"begin;"}", "#{<<~'end;'}", rss: true)
+    a = RubyVM::InstructionSequence.compile("foo(bar: :baz)").to_binary
+    begin;
+      1_000_000.times do
+        RubyVM::InstructionSequence.load_from_binary(a)
+      end
+    end;
+  end
 end