git: openjdk/loom: fibers: get rid of notifyJvmtiTerminated: post VirtualThreadEnd in notifyJvmtiUnmountBegin

[duke]

Changeset: 62930db3
Author:    Serguei Spitsyn <serguei.spitsyn at oracle.com>
Date:      2021-04-02 19:32:30 +0000
URL:       https://git.openjdk.java.net/loom/commit/62930db3

get rid of notifyJvmtiTerminated: post VirtualThreadEnd in notifyJvmtiUnmountBegin

! src/hotspot/share/include/jvm.h
! src/hotspot/share/prims/jvm.cpp
! src/java.base/share/classes/java/lang/VirtualThread.java
! src/java.base/share/native/libjava/VirtualThread.c
! test/hotspot/jtreg/serviceability/jvmti/vthread/DoContinueSingleStepTest/libDoContinueSingleStepTest.cpp