RFR: 8343506: [s390x] multiple test failures with ubsan

[Amit Kumar]

On Wed, 6 Nov 2024 00:56:24 GMT, Dean Long <dlong at openjdk.org> wrote:

>> I don't think this is necessary. Unsigned subtraction with wrap-around is not undefined behavior.
>
> Right, it's not UB, but sometimes it is a bug, and would be flagged by things like -fsanitize=unsigned-integer-overflow, so my preference would be to avoid it if possible.

As it is not really required and for `storage to storage` instructions `length = 0` is invalid case, which current code is already taking care of. So I would just simply keep it that way.

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PR Review Comment: https://git.openjdk.org/jdk/pull/21864#discussion_r1834351053