7066063: CMS: "Conservation Principle" assert failed

Add call to coalBirth() in CompactibleFreeListSpace::reset()

Reviewed-by: ysr, jmasa
diff --git a/hotspot/src/share/vm/gc_implementation/concurrentMarkSweep/compactibleFreeListSpace.cpp b/hotspot/src/share/vm/gc_implementation/concurrentMarkSweep/compactibleFreeListSpace.cpp
index 6ba15a2..b0c9ec8 100644
--- a/hotspot/src/share/vm/gc_implementation/concurrentMarkSweep/compactibleFreeListSpace.cpp
+++ b/hotspot/src/share/vm/gc_implementation/concurrentMarkSweep/compactibleFreeListSpace.cpp
@@ -285,6 +285,7 @@
       _bt.verify_not_unallocated((HeapWord*)fc, fc->size());
       _indexedFreeList[mr.word_size()].return_chunk_at_head(fc);
     }
+    coalBirth(mr.word_size());
   }
   _promoInfo.reset();
   _smallLinearAllocBlock._ptr = NULL;