git: openjdk/loom: fibers: JVMTI update for virtual threads

[duke]

Changeset: 3ea45315
Author:    Serguei Spitsyn <serguei.spitsyn at oracle.com>
Date:      2020-01-11 10:00:14 +0000
URL:       https://git.openjdk.java.net/loom/commit/3ea45315

JVMTI update for virtual threads

+ test/hotspot/jtreg/serviceability/jvmti/FiberMonitorTest/FiberMonitorTest.java
+ test/hotspot/jtreg/serviceability/jvmti/FiberMonitorTest/libFiberMonitorTest.c