git: openjdk/loom: fibers: Remove _keepalive WeakHandle remnants.

[duke]

Changeset: 42881d1e
Author:    Coleen Phillimore <coleenp at openjdk.org>
Committer: Ron Pressler <rpressler at openjdk.org>
Date:      2021-05-10 17:04:27 +0000
URL:       https://git.openjdk.java.net/loom/commit/42881d1e1a772449bce9de05c4778a53f2b81545

Remove _keepalive WeakHandle remnants.

Reviewed-by: eosterlund

! src/hotspot/share/code/compiledMethod.cpp
! src/hotspot/share/code/compiledMethod.hpp
! src/hotspot/share/code/compiledMethod.inline.hpp
! src/hotspot/share/code/nmethod.cpp
! src/hotspot/share/code/nmethod.hpp
! src/hotspot/share/gc/g1/g1CodeBlobClosure.cpp
! src/hotspot/share/gc/z/zBarrierSetNMethod.cpp
! src/hotspot/share/gc/z/zHeapIterator.cpp
! src/hotspot/share/gc/z/zMark.cpp
! src/hotspot/share/gc/z/zNMethod.cpp
! src/hotspot/share/gc/z/zNMethod.hpp
! src/hotspot/share/gc/z/zUnload.cpp
! src/hotspot/share/gc/z/zVerify.cpp
! src/hotspot/share/memory/iterator.cpp
! src/hotspot/share/runtime/continuation.hpp