git: openjdk/loom: fibers: Allow pollerMode=3 when using custom default scheduler

[duke]

Changeset: 488d1806
Branch: fibers
Author:    Alan Bateman <alan.bateman at oracle.com>
Date:      2025-11-10 10:19:07 +0000
URL:       https://git.openjdk.org/loom/commit/488d18069773fdc4c8d52a1678649b415c4738bf

Allow pollerMode=3 when using custom default scheduler

! src/java.base/share/classes/java/lang/ThreadBuilders.java
! test/jdk/java/lang/Thread/virtual/CustomDefaultScheduler.java