Adjust limit for booted memory test.

a previous change decreased the size of a zone object and it seems
that sometimes the OS report more memory used even though there
is less zone allocation.
Review URL: https://chromiumcodereview.appspot.com/9443019

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@10814 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

test/cctest/test-mark-compact.cc

@@ -542,7 +542,7 @@ TEST(BootUpMemoryUse) {
       if (v8::internal::Snapshot::IsEnabled()) {
         CHECK_LE(booted_memory - initial_memory, 6532 * 1024);  // 6388.
       } else {
-        CHECK_LE(booted_memory - initial_memory, 6686 * 1024);  // 6456
+        CHECK_LE(booted_memory - initial_memory, 6940 * 1024);  // 6456
       }
     }
   }