Use separate sweeper thread; enables more aggressive sweeping. Reviewed-by: kvn, jrose
Reviewed-by: kvn, iignatyev, mgerdin
Change checks for isHumongous() to continuesHumongous() as installing a code root for a humongous object is valid, but not for continuations of humongous objects. Cleaned up asserts. Reviewed-by: jmasa, tamao