8004504: ListBuffer could reuse List.nil() as the sentinel element
Summary: ListBuffer.last now points to the last elements with client data, or null if none.
Reviewed-by: jjg, mcimadamore
.level= INFO
MemoryHandlerTest$CustomMemoryHandler.push=WARNING
MemoryHandlerTest$CustomMemoryHandlerNoTarget.push=WARNING
MemoryHandlerTest$CustomMemoryHandler.target=MemoryHandlerTest$CustomTargetHandler
handlers=java.util.logging.ConsoleHandler,MemoryHandlerTest$CustomMemoryHandler,MemoryHandlerTest$CustomMemoryHandlerNoTarget
java.util.logging.ConsoleHandler.formatter = java.util.logging.SimpleFormatter
java.util.logging.ConsoleHandler.level = INFO
java.util.logging.MemoryHandler.target=MemoryHandlerTest$SimpleTargetHandler
java.util.logging.MemoryHandler.push = INFO