8220030: JdbStopThreadidTest.java failed due to "Unexpected IO error while writing command 'quit' to jdb stdin stream" Summary: Use contToExit(1) for safer approach to test exit. Reviewed-by: gadams, amenkov

8219946: Set class on body elements Reviewed-by: hannesw

8220164: Fix build instructions for AIX Reviewed-by: mdoerr, erikj, mbaesken

8220161: Shenandoah does not need to initialize PLABs for safepoint workers Reviewed-by: shade