RFR: 8287686: Add assertion to ensure that disarm value offset < 128

[Zhengyu Gu]

On Fri, 3 Jun 2022 07:40:16 GMT, Thomas Schatzl <tschatzl at openjdk.org> wrote:

>> Please review this trivial patch to ensure disarm value offset is less than 128.
>> 
>> At least on x86_64, nmethod entry barrier encodes disarmed value offset as disp8 immed, overflowing the value can result crashes, see [JDK-8244420](https://bugs.openjdk.java.net/browse/JDK-8244420) for details.
>> 
>> Test:
>> 
>> - [x] jdk_loom and hotspot_loom on Linux x86_64
>
> Marked as reviewed by tschatzl (Reviewer).

Thanks, @tschatzl @shipilev

-------------

PR: https://git.openjdk.java.net/jdk/pull/8977