Moved zones and zone related stuff in its own directory.

test/unittests/compiler/zone-pool-unittest.cc

Index: test/unittests/compiler/zone-pool-unittest.cc
diff --git a/test/unittests/compiler/zone-pool-unittest.cc b/test/unittests/compiler/zone-pool-unittest.cc
index 47f1cc5c752adde7990ebc75f5d1967081a3f7f9..5bbdbfd45dd21bbd6be96c21650f28e0a810da51 100644
--- a/test/unittests/compiler/zone-pool-unittest.cc
+++ b/test/unittests/compiler/zone-pool-unittest.cc
@@ -38,7 +38,7 @@ class ZonePoolTest : public TestWithIsolate {
   }
 
  private:
-  base::AccountingAllocator allocator_;
+  v8::internal::AccountingAllocator allocator_;
   ZonePool zone_pool_;
   base::RandomNumberGenerator rng;
 };