Add a test for [ruby-core:27247]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@26144 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

test/ruby/test_regexp.rb

@@ -10,6 +10,10 @@ class TestRegexp < Test::Unit::TestCase
     $VERBOSE = @verbose
   end
 
+  def test_ruby_core_27247
+    assert_match(/(a){2}z/, "aaz")
+  end
+
   def test_ruby_dev_24643
     assert_nothing_raised("[ruby-dev:24643]") {
       /(?:(?:[a]*[a])?b)*a*$/ =~ "aabaaca"