RFR: 8323122: AArch64: Increase itable stub size estimate

[Evgeny Astigeevich]

On Wed, 10 Jan 2024 02:03:08 GMT, Yude Lin <duke at openjdk.org> wrote:

> Since [JDK-8307352](https://bugs.openjdk.org/browse/JDK-8307352), itable stub size has grown by 20 bytes on linux-aarch64. In particular, the "slop-counted" code increases from 100->120 bytes, where the current estimate is 124 bytes. I haven't found a case where it exceeds the estimate. For now this size is stable across the few linux-aarch64 configurations I ran with. It doesn't vary (for example) by different klass decoding schemes. But I think the idea of the estimate is that we can never know. I propose we increase the estimate to be safe.
> 
> Passed hotspot/jtreg/:tier1

lgtm

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Marked as reviewed by eastigeevich (Committer).

PR Review: https://git.openjdk.org/jdk/pull/17336#pullrequestreview-1821943502