test_alias.rb: rename duplicate name

	* test/ruby/test_alias.rb (test_alias_wb_miss): rename duplicate
  name to get rid of redefinition.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_1@44788 b2dd03c8-39d4-4d8f-98ff-823fe69b080e