RFR: 8366155: Serial: Obsolete PretenureSizeThreshold

[Thomas Schatzl]

On Tue, 26 Aug 2025 11:44:35 GMT, Albert Mingkun Yang <ayang at openjdk.org> wrote:

> Remove obj-size checking before young/old-gen allocation -- an allocation succeeds iff there is enough free space.
> 
> This simplifies the allocation logic:
> 1. before attempting gc: `mem_allocate_work` does young-gen allocation then old-gen-no-expansion allocation
> 2. after gc (still inside gc safepoint): `satisfy_failed_allocation` does young-gen allocation old-gen-with-expansion allocation
> 
> Test: tier1-3

Seems good.

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Marked as reviewed by tschatzl (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/26941#pullrequestreview-3173572869