[rubygems/rubygems] Remove no longer needed condition

The `force-ruby-platform` settings is properly respected when
materializing since rubygems/rubygems@e17d7e9efb91.

rubygems/rubygems@c4ba54eb96

Author: deivid-rodriguez

lib/bundler/definition.rb

@@ -650,7 +650,6 @@ def pin_locally_available_names(source_requirements)
 
     def current_ruby_platform_locked?
       return false unless generic_local_platform_is_ruby?
-      return false if Bundler.settings[:force_ruby_platform] && !@platforms.include?(Gem::Platform::RUBY)
 
       current_platform_locked?
     end