RFR (xs) 8075967: Zero interpreter asserts for SafeFetch<32, N> calls in ObjectMonitor

[Coleen Phillimore]

Summary: Implement SafeFetchX unsafely and make CanUseSafeFetchX false 
for Zero

Also, this fixes a couple other minor issues.

Ran jdk9 jck tests with one timeout.  hotspot/runtime jtreg tests don't 
run because Zero doesn't support UseCompressedOops (not sure why) and 
CDS (know why).

open webrev at http://cr.openjdk.java.net/~coleenp/8075967/
bug link https://bugs.openjdk.java.net/browse/JDK-8075967

Thanks,
Coleen