hg: shenandoah/jdk11: [backport] 8240917: Shenandoah: Avoid scanning thread code roots twice in all root scanner

[zgu at redhat.com]

Changeset: be750117a860
Author:    zgu
Date:      2020-03-12 13:08 -0400
URL:       https://hg.openjdk.java.net/shenandoah/jdk11/rev/be750117a860

[backport] 8240917: Shenandoah: Avoid scanning thread code roots twice in all root scanner
Reviewed-by: rkennke

! src/hotspot/share/gc/shenandoah/shenandoahRootProcessor.inline.hpp