I fix order of actual and expect test value in indexerror.rb.

test/t/indexerror.rb

@@ -2,9 +2,9 @@
 # IndexError ISO Test
 
 assert('IndexError', '15.2.33') do
-  assert_equal IndexError.class, Class
+  assert_equal Class, IndexError.class
 end
 
 assert('IndexError superclass', '15.2.33.2') do
-  assert_equal IndexError.superclass, StandardError
+  assert_equal StandardError, IndexError.superclass
 end