Tests for comma in HashedCollection, allowing comma

Pharo has comma for Dictionaries.
Update API-CHANGES.txt
Merge branch 'upstream' into allow-comma-for-hashedcollection
Merge branch 'allow-comma-for-hashedcollection' of https://github.com/herby/amber into herby-allow-comma-for-hashedcollection

Conflicts:
	API-CHANGES.txt