RFR: Report actual free size in non-verbose FreeSet status

[Aleksey Shipilev]

It misleadingly prints "Free:" for the entire capacity, which only makes sense when no allocations
happened yet. Easy fix:

diff -r 55965025794c src/hotspot/share/gc/shenandoah/shenandoahFreeSet.cpp
--- a/src/hotspot/share/gc/shenandoah/shenandoahFreeSet.cpp     Thu Jul 12 12:04:55 2018 +0200
+++ b/src/hotspot/share/gc/shenandoah/shenandoahFreeSet.cpp     Thu Jul 12 12:19:26 2018 +0200
@@ -456,7 +456,7 @@

 void ShenandoahFreeSet::log_status() {
   log_info(gc, ergo)("Free: " SIZE_FORMAT "M, Regions: " SIZE_FORMAT " mutator, " SIZE_FORMAT "
collector",
-                     capacity() / M, mutator_count(), collector_count());
+                     available() / M, mutator_count(), collector_count());
 }

 void ShenandoahFreeSet::log_status_verbose() {

Testing: eyeballing logs

Thanks,
-Aleksey