[13] RFR (S): 8218879: Keep track of memory accesses originated from Unsafe

[Vladimir Ivanov]

http://cr.openjdk.java.net/~vlivanov/8218879/webrev.00/
https://bugs.openjdk.java.net/browse/JDK-8218879

It may be useful to differentiate memory accesses originated from 
bytecode and Unsafe.

While JVM performs access checks for field accesses and range checks for 
array accesses, it's user responsibility to perform all necessary checks 
to ensure safety when it comes to Unsafe.

 From compiler perspective, it may be useful to distinguish between 
those when it matters what kind of checks have been performed.

Testing: hs-precheckin-comp, tier1-5

Best regards,
Vladimir Ivanov