418636 Name anonymous filter and holders with classname-hashcode

Conflicts:
	jetty-servlet/src/main/java/org/eclipse/jetty/servlet/ServletHandler.java
	jetty-servlet/src/main/java/org/eclipse/jetty/servlet/ServletHolder.java
	jetty-servlet/src/test/java/org/eclipse/jetty/servlet/ErrorPageTest.java
418636 Name anonymous filter and holders with classname-hashcode

Conflicts:
	jetty-servlet/src/main/java/org/eclipse/jetty/servlet/ServletHandler.java
	jetty-servlet/src/main/java/org/eclipse/jetty/servlet/ServletHolder.java
Merge remote-tracking branch 'origin/master' into jetty-9.1

Conflicts:
	jetty-servlet/src/test/java/org/eclipse/jetty/servlet/ErrorPageTest.java