test for [ruby-dev:31592].

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@13230 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

bootstraptest/test_knownbug.rb

@@ -5,5 +5,6 @@
 
 # massign
 assert_equal '2', 'a, a = 1, 2; a', "[ruby-dev:31522]"
+assert_equal '[0,1,{2=>3}]', '[0,*[1],2=>3]', "[ruby-dev:31592]"