git: openjdk/loom: fibers: minor tweak in VThreadMonitorTest to avoid a JNI IsSameObject assert

[duke]

Changeset: d54d1604
Author:    Serguei Spitsyn <serguei.spitsyn at oracle.com>
Date:      2021-10-14 15:25:18 +0000
URL:       https://git.openjdk.java.net/loom/commit/d54d16048c67ff0e467462f2fd989c1ea84c13c4

minor tweak in VThreadMonitorTest to avoid a JNI IsSameObject assert

! test/hotspot/jtreg/serviceability/jvmti/vthread/VThreadMonitorTest/libVThreadMonitorTest.cpp