[11u] RFR/RFC: Backport the remaining test for JDK-8220714

[Roman Kennke]

Yes, thanks!

Roman


> We have a special bug:
>  https://bugs.openjdk.java.net/browse/JDK-8220714
> 
> It has shared fix, backported to 11.0.4, and we got it in sh/jdk11 with regular merge. And there is
> Shenandoah-specific test that was obviously missing in upstream backports, and we need to backport
> it separately. This is it:
> 
> $ hg qdiff --stat
>  test/hotspot/jtreg/gc/shenandoah/compiler/TestUnsafeOffheapSwap.java |  109
> +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 files changed, 109 insertions(+), 0 deletions(-)
> 
> [backport] 8220714: C2 Compilation failure when accessing off-heap memory using Unsafe
> Reviewed-by: vlivanov, roland
> 
> $ hg export
> --- /dev/null   Thu Jan 01 00:00:00 1970 +0000
> +++ b/test/hotspot/jtreg/gc/shenandoah/compiler/TestUnsafeOffheapSwap.java      Fri Mar 15 09:57:42
> 2019 +0100
> @@ -0,0 +1,109 @@
> +/*
> + * Copyright (c) 2019, Red Hat, Inc. All rights reserved.
> + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
> + *
> + * This code is free software; you can redistribute it and/or modify it
> + * under the terms of the GNU General Public License version 2 only, as
> + * published by the Free Software Foundation.
> + *
> ...
> 
> Testing: new test, with/without Graal
>