[11u] RFR: 8235829: graal crashes with Zombie.java test

[Lindenmaier, Goetz]

Hi,

I am downporting this for parity with 11.0.10-oracle.

http://cr.openjdk.java.net/~goetz/wr20/8235823-graal_zombie_crash-jdk11/01/

The original change adds a lot of BarrierSetNMethod barriers.
This barrier type does not exist in 11. It is not needed as no
concurrent class unloading is implemented in 11. That was added upstream
for ZGC and Shenandoah.
I omitted this coding.

https://bugs.openjdk.java.net/browse/JDK-8235829
https://hg.openjdk.java.net/jdk/jdk14/rev/26bb0fe2270a

Best regards,
  Goetz.