git: openjdk/loom: fibers: Track number of vthreads in runningVThreads so we don't need to count them threadControl_allVThreads().

[duke]

Changeset: 1c1e0f9a
Author:    Chris Plummer <chris.plummer at oracle.com>
Date:      2022-02-28 07:15:17 +0000
URL:       https://git.openjdk.java.net/loom/commit/1c1e0f9a498c36fd4617f898c1e23b1befa442cd

Track number of vthreads in runningVThreads so we don't need to count them threadControl_allVThreads().

! src/jdk.jdwp.agent/share/native/libjdwp/threadControl.c