Increasing the variety of Gzip tests per recommendations by Simone
Merge branch 'jetty-9.2.x'

Conflicts:
	jetty-servlets/src/test/java/org/eclipse/jetty/server/handler/gzip/AsyncScheduledWrite.java
	jetty-servlets/src/test/java/org/eclipse/jetty/server/handler/gzip/AsyncTimeoutDispatchBasedWrite.java
	jetty-servlets/src/test/java/org/eclipse/jetty/server/handler/gzip/AsyncTimeoutWrite.java
	jetty-servlets/src/test/java/org/eclipse/jetty/server/handler/gzip/GzipContentLengthTest.java
	jetty-servlets/src/test/java/org/eclipse/jetty/servlets/GzipFilterLayeredTest.java
	jetty-servlets/src/test/java/org/eclipse/jetty/servlets/gzip/AsyncScheduledDispatchWrite.java
	jetty-servlets/src/test/java/org/eclipse/jetty/servlets/gzip/AsyncScheduledWrite.java
	jetty-servlets/src/test/java/org/eclipse/jetty/servlets/gzip/AsyncTimeoutCompleteWrite.java
	jetty-servlets/src/test/java/org/eclipse/jetty/servlets/gzip/AsyncTimeoutDispatchBasedWrite.java
	jetty-servlets/src/test/java/org/eclipse/jetty/servlets/gzip/AsyncTimeoutDispatchWrite.java
	jetty-servlets/src/test/java/org/eclipse/jetty/servlets/gzip/AsyncTimeoutWrite.java