git: openjdk/loom: fibers: fixed two issues in JVMTI support for fibers; added one more check into FiberTest

[duke]

Changeset: 1011c862
Author:    Serguei Spitsyn <serguei.spitsyn at oracle.com>
Date:      2019-10-28 09:53:47 +0000
URL:       https://git.openjdk.java.net/loom/commit/1011c862

fixed two issues in JVMTI support for fibers; added one more check into FiberTest

! src/hotspot/share/prims/jvmtiEnvBase.cpp
! src/hotspot/share/prims/jvmtiExport.cpp
! test/hotspot/jtreg/serviceability/jvmti/FiberTest/libFiberTest.c