git: openjdk/jdk: 8255400: Shenandoah: C2 failures after JDK-8255000

[Roland Westrelin]

Changeset: a3aad119
Author:    Roland Westrelin <roland at openjdk.org>
Date:      2020-11-02 15:48:14 +0000
URL:       https://github.com/openjdk/jdk/commit/a3aad119

8255400: Shenandoah: C2 failures after JDK-8255000

Reviewed-by: rkennke

! src/hotspot/share/gc/shenandoah/c2/shenandoahSupport.cpp
+ test/hotspot/jtreg/gc/shenandoah/compiler/TestBarrierExpansionDeadMemPhi.java