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

[Aleksey Shipilev]

On Wed, 1 Jun 2022 18:06:52 GMT, Zhengyu Gu <zgu 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

Looks fine.

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Marked as reviewed by shade (Reviewer).

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