RFR: 8370943: Support heap expansion during startup in Serial and Parallel

[Albert Mingkun Yang]

On Thu, 30 Oct 2025 11:41:20 GMT, Albert Mingkun Yang <ayang at openjdk.org> wrote:

> Add heap expansion logic in allocation slow-path during startup. Some asserts are relaxed to be used by java-threads and outside of safepoint.
> 
> Test: tier1-5

Thanks for review.

-------------

PR Comment: https://git.openjdk.org/jdk/pull/28059#issuecomment-3473106521