HHH-8217 Make generated constraint names short and non-random

Conflicts:
	hibernate-core/src/main/java/org/hibernate/cfg/AnnotationBinder.java
	hibernate-core/src/main/java/org/hibernate/cfg/Configuration.java
	hibernate-core/src/main/java/org/hibernate/mapping/Constraint.java
	hibernate-core/src/main/java/org/hibernate/mapping/UniqueKey.java