MEMMOVE if with arguments. Patch by @ksss [fix GH-537] * test/ruby/test_array.rb: ditto. * benchmark/bm_array_shift.rb: Added benchmark of GH-537 issue. git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@49114 b2dd03c8-39d4-4d8f-98ff-823fe69b080e