RFR(M) 8222992: Shenandoah: Pre-evacuate all roots

[Aleksey Shipilev]

On 5/1/19 4:22 PM, Zhengyu Gu wrote:
> Updated webrev: http://cr.openjdk.java.net/~zgu/JDK-8222992/webrev.02/index.html

This looks okay to me.

Not a fan of the separate ShenandoahVerifier::verify_roots_no_forwarded, since we could "just" fold
stronger (non-forwarded) root verification to the generic verification code (e.g. in
ShenandoahVerifierReachableTask). That, however, might end up with some failures in Traversal and
such. We can do that as follow-up.

-- 
Thanks,
-Aleksey