CallSite dependency tracking is broken after sun.misc.Cleaner became automatically cleared

This TEST: compiler/jsr292/CallSiteDepContextTest.java,
from the c[1 2]-hotspot_compiler_3 set,
is failing after merging jdk9/dev with jdk9/hs (on all platforms).

#
# A fatal error has been detected by the Java Runtime Environment:
#
# SIGSEGV (0xb) at pc=0x402ba786, pid=31324, tid=0x53bb6b90
#
# JRE version: Java(TM) SE Runtime Environment (9.0) (build 1.9.0-internal-fastdebug-20150501110205.amurillo.jdk9-hs-2015-04--b00)
# Java VM: Java HotSpot(TM) Client VM (1.9.0-internal-fastdebug-20150501110205.amurillo.jdk9-hs-2015-04--b00 mixed mode linux-x86 )
# Problematic frame:
# V [libjvm.so+0x28d786] ciCallSite::get_context()+0x2f6
#

this is happening after merging with jdk9/dev. It passed for the comp to hs pushing job,
so I suspect it's related to changes coming from jdk9/dev/hotspot.
Note that that specific test is excluded in jdk9/dev (not run on jkd9/dev jprt jobs with "-testset hotspot")