git: openjdk/loom: fibers: 1. Fix GetThreadState for unattached cthreads; 2. Fix GetVirtualThread inccorrectly returning NULL sometimes

[duke]

Changeset: ee931f57
Author:    Serguei Spitsyn <serguei.spitsyn at oracle.com>
Date:      2021-04-27 03:08:32 +0000
URL:       https://git.openjdk.java.net/loom/commit/ee931f57

1. Fix GetThreadState for unattached cthreads; 2. Fix GetVirtualThread inccorrectly returning NULL sometimes

! src/hotspot/share/prims/jvmtiEnvBase.cpp
! src/hotspot/share/prims/jvmtiEventController.cpp
! src/hotspot/share/prims/jvmtiExtensions.cpp
! src/hotspot/share/prims/jvmtiImpl.cpp
! test/hotspot/jtreg/serviceability/jvmti/stress/StackTrace/Suspended/libGetStackTraceSuspendedStress.cpp