RFR: 8348858: [leyden] Bump the default code buffer sizes to store more generated code

[Aleksey Shipilev]

On Wed, 29 Jan 2025 19:28:47 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

>> On other hand this line change affects only requested size and not how final instructions section size is calculated. So it could be fine.
>
> Dang. I have not realized this is a possible input to inline heuristics. Let me see if it is affecting anything, and/or if I can avoid touching this part.

Yeah, this affects inlining heuristics in a major way, like the issues you have linked described. Additionally, I realized the whole `estimate_stub_size` does not actually work well: https://github.com/openjdk/jdk/pull/23333#issuecomment-2624140301. So I am making a lateral move here, and fixing C2 stub barrier expansion code directly for Leyden.

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PR Review Comment: https://git.openjdk.org/leyden/pull/28#discussion_r1935449261