git: openjdk/loom: fibers: Restore threadDump.schema.json, more cleanup

[duke]

Changeset: 668a167e
Branch: fibers
Author:    Alan Bateman <alan.bateman at oracle.com>
Date:      2025-05-05 14:14:31 +0000
URL:       https://git.openjdk.org/loom/commit/668a167ebb897a5c5ebdeca059a424580483982b

Restore threadDump.schema.json, more cleanup

! src/java.base/share/classes/jdk/internal/vm/ThreadDumper.java
! src/jdk.management/share/classes/com/sun/management/HotSpotDiagnosticMXBean.java
+ src/jdk.management/share/classes/com/sun/management/doc-files/threadDump.schema.json
! src/jdk.management/share/classes/com/sun/management/internal/HotSpotDiagnostic.java