RFR(XS): Cleanup: removed redundant ClassLoaderData::clear_claimed_marks() call

[Zhengyu Gu]

Now, the call is encapsulated in ShenandoahRootProcessor's cld_iterator.

Webrev: 
http://cr.openjdk.java.net/~zgu/shenandoah/redundant_clear_cld/webrev.00/

Test:

  hotspot_gc_shenandoah test with fastdebug and release builds.

Thanks,

-Zhengyu