[11] RFR: 2019-11-01, Follow-up backports to sh/jdk11

[Aleksey Shipilev]

Hi,

I would like to push two follow-up backports to sh/jdk11:
 [backport] 8233303: Shenandoah: verifier assert erroneously uses byte_size_in_exact_unit
 [backport] 8233387: Shenandoah: passive mode should disable pacing ergonomically

Webrev:
  https://cr.openjdk.java.net/~shade/shenandoah/backports/jdk11-20191101/webrev.01/

Testing: hotspot_gc_shenandoah {fastdebug, release}

-- 
Thanks,
-Aleksey