hg: loom/loom: do full thread transition if capability can_support_fibers is enabled

[serguei.spitsyn at oracle.com]

Changeset: b5999e4e2982
Author:    sspitsyn
Date:      2019-05-02 08:48 -0700
URL:       http://hg.openjdk.java.net/loom/loom/rev/b5999e4e2982

do full thread transition if capability can_support_fibers is enabled

! src/hotspot/cpu/x86/stubGenerator_x86_64.cpp
! src/hotspot/share/prims/jvmtiExport.cpp
! src/hotspot/share/prims/jvmtiExport.hpp
! src/hotspot/share/prims/jvmtiManageCapabilities.cpp