git: openjdk/loom: fibers: Fix fast-path detection

[duke]

Changeset: 5e1d2835
Author:    Ron Pressler <ron.pressler at oracle.com>
Date:      2020-08-06 15:44:59 +0000
URL:       https://git.openjdk.java.net/loom/commit/5e1d2835

Fix fast-path detection

! src/hotspot/cpu/x86/sharedRuntime_x86_64.cpp
! src/hotspot/cpu/x86/stubGenerator_x86_64.cpp
! src/hotspot/share/runtime/continuation.cpp