Disable the CC collector verbose log.

To reduce the amount of buildbot libcore test logs.

Bug: 12687968
Change-Id: Idadca6622c745ef12629ccb26dcbdc9ebc379a00
diff --git a/runtime/gc/collector/concurrent_copying.h b/runtime/gc/collector/concurrent_copying.h
index 5d21c59..76315fe 100644
--- a/runtime/gc/collector/concurrent_copying.h
+++ b/runtime/gc/collector/concurrent_copying.h
@@ -57,7 +57,7 @@
   // Enable the from-space bytes/objects check.
   static constexpr bool kEnableFromSpaceAccountingCheck = true;
   // Enable verbose mode.
-  static constexpr bool kVerboseMode = true;
+  static constexpr bool kVerboseMode = false;
 
   ConcurrentCopying(Heap* heap, const std::string& name_prefix = "");
   ~ConcurrentCopying();