hg: jdk/sandbox: 8214025: assert(t->singleton()) failed: must be a constant when ScavengeRootsInCode < 2

[chris.hegarty at oracle.com]

Changeset: 85283f9565da
Author:    thartmann
Date:      2018-11-21 15:05 +0100
URL:       http://hg.openjdk.java.net/jdk/sandbox/rev/85283f9565da

8214025: assert(t->singleton()) failed: must be a constant when ScavengeRootsInCode < 2
Summary: Added missing null checks and checks for pending exception.
Reviewed-by: kvn

! src/hotspot/share/opto/doCall.cpp
+ test/hotspot/jtreg/compiler/arguments/TestScavengeRootsInCode.java