RFR (S): 8138740: Start initial mark right after mixed GC if needed

[Thomas Schatzl]

Hi all,

  can I have reviews for this small change that makes the marking cycle
start faster, to potentially allow marking to complete in time if mixed
gc does not clear out just enough memory for otherwise making the
marking cycle not complete?

CR:
https://bugs.openjdk.java.net/browse/JDK-8138740
Webrev:
http://cr.openjdk.java.net/~tschatzl/8138740/webrev/
Testing:
jprt, vm.gc, manual testing

Thanks,
  Thomas