[11u] RFR (S) 8218879: Keep track of memory accesses originated from Unsafe

[Aleksey Shipilev]

Resending with proper subject "[11u] ...":

On 8/7/19 12:15 PM, Aleksey Shipilev wrote:
> Original RFE:
>   https://bugs.openjdk.java.net/browse/JDK-8218879
>   https://hg.openjdk.java.net/jdk/jdk/rev/e002408eb0c0
> 
> This is needed to get the infrastructure for the follow-up backports (e.g. JDK-8224658). If we don't
> do this, parts of this patch would inevitably leak into 11u with those backports. Patch does not
> apply cleanly, because context is changed in some places.
> 
> 11u webrev:
>   https://cr.openjdk.java.net/~shade/8218879/webrev.11u.01/
> 
> Testing: tier1, tier2.