git: openjdk/loom: fibers: STS updates

[duke]

Changeset: cf9b521e
Author:    Alan Bateman <alan.bateman at oracle.com>
Date:      2023-05-18 17:03:52 +0000
URL:       https://git.openjdk.org/loom/commit/cf9b521e57e9120263784bb7bb678b358ff0e60c

STS updates
- TaskHandle -> Substack
- Change State to reflect state of subtask
- Remi's suggestion for generic signatures
- csm API to help logging

! src/java.base/share/classes/java/util/concurrent/StructuredTaskScope.java
! src/java.base/share/classes/module-info.java
+ src/jdk.management/share/classes/com/sun/management/Threads.java
! test/jdk/TEST.groups
+ test/jdk/com/sun/management/Threads/CurrentThreadEnclosingScopes.java
! test/jdk/java/util/concurrent/StructuredTaskScope/StructuredTaskScopeTest.java
! test/jdk/java/util/concurrent/StructuredTaskScope/WithScopedValue.java