Skip test_gem_with_platform_and_platform_dependencies only ruby/ruby repository

test/rubygems/test_gem_commands_exec_command.rb

@@ -216,7 +216,7 @@ class TestGemCommandsExecCommand < Gem::TestCase
 
   def test_gem_with_platform_and_platform_dependencies
     pend "extensions don't quite work on jruby" if Gem.java_platform?
-    pend "terminates on mswin" if Gem.win_platform?
+    pend "terminates on mswin" if Gem.win_platform? && ruby_repo?
 
     spec_fetcher do |fetcher|
       fetcher.download "a", 2 do |s|