RFR: 8275298: Remove unnecessary weak_oops_do call in adjust weak roots phase

[Stefan Johansson]

On Thu, 14 Oct 2021 18:43:44 GMT, Albert Mingkun Yang <ayang at openjdk.org> wrote:

> This PR consists of two logical steps in two commits:
> 
> 1. change `weak_oops_do` to `verify_no_references_recorded` to check discovered lists (DL) are indeed empty during adjust-weak-roots phase
> 2. Move the assertion to the end of ref-processing, since elements on DL are not really related to "weak roots"
> 
> Test: tier1-6

Looks good

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Marked as reviewed by sjohanss (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/5957