RFR(sh/jdk8): [backport] 8228369: Shenandoah: Refactor LRB C1 stubs

[Aleksey Shipilev]

On 11/25/20 10:23 PM, Roman Kennke wrote:
> It turns out that the aarch64 parts have been incorrect. Please review
> this webrev instead:
> 
> http://cr.openjdk.java.net/~rkennke/JDK-8228369-jdk8/webrev.01/

I believe we need to protect new blocks in c1_LIRAssembler_aarch64.cpp with UseShenandoahGC?

Otherwise looks good.

-- 
Thanks,
-Aleksey