Build #267 (May 12, 2019 9:20:01 AM)

1. - add two tests for HistorySlot related to adding  slots to existing (detail / githubweb)
2. Update src/Collections-Support/Association.class.st (detail / githubweb)
3. Update src/Slot-Core/LiteralVariable.class.st (detail / githubweb)

Push event to branch Pharo8.0 at 9:19:55 AM on May 12, 2019

• Pharo8.0

• unix-32 / Tests-unix-32 / Unix32.Announcements.Tests.Core.Tests.WeakAnnouncerTest.testNoDeadWeakSubscriptions
• unix-32 / Tests-unix-32 / Unix32.Tests.SystemChangeNotification.SystemAnnouncerLiveTest.testNoDeadSubscriptions
• windows-32 / Tests-windows-32 / Windows32.Announcements.Tests.Core.Tests.WeakAnnouncerTest.testNoDeadWeakSubscriptions
• windows-32 / Tests-windows-32 / Windows32.Tests.SystemChangeNotification.SystemAnnouncerLiveTest.testNoDeadSubscriptions