RFR: 8231242: G1CollectedHeap::print_regions_on lost description for "OA" and "CA"

[huangjia]

Hi all,

JBS: https://bugs.openjdk.java.net/browse/JDK-8231242

When dumping the info of heap region, the description for "OA" and "CA" 
seems to be lost.
Please review the following fix which improves the readability of the 
heap region log.
-----------------------------------
diff -r 778fc2dcbdaa src/hotspot/share/gc/g1/g1CollectedHeap.cpp
--- a/src/hotspot/share/gc/g1/g1CollectedHeap.cpp       Wed Sep 18 
20:49:13 2019 -0400
+++ b/src/hotspot/share/gc/g1/g1CollectedHeap.cpp       Thu Sep 19 
11:47:07 2019 +0800
@@ -2378,6 +2378,7 @@
    st->print_cr("Heap Regions: E=young(eden), S=young(survivor), O=old, "
                 "HS=humongous(starts), HC=humongous(continues), "
                 "CS=collection set, F=free, A=archive, "
+               "OA=open archive, CA=closed archive, "
                 "TAMS=top-at-mark-start (previous, next)");
    PrintRegionClosure blk(st);
    heap_region_iterate(&blk);
-----------------------------------
For more info, please see the JBS.

Testing:
    - make test TEST="jtreg:hotspot_gc" CONF=release
    - make test TEST="jtreg:hotspot_gc" CONF=fastdebug

Thanks a lot

Best regards,
Jia