RFR: 8378178: Change Thread::_allocated_bytes from jlong to uint64_t

[Stefan Karlsson]

On Wed, 18 Feb 2026 15:04:21 GMT, Albert Mingkun Yang <ayang at openjdk.org> wrote:

> Replace `jlong` with `uint64_t` for `Thread::_allocated_bytes` and `ThreadService::_exited_allocated_bytes`.
> 
> Test: tier1

Marked as reviewed by stefank (Reviewer).

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PR Review: https://git.openjdk.org/jdk/pull/29792#pullrequestreview-3820620308