Fix the unit test failure in devbox

Summary:
My last diff was developed in MacOS but in devserver environment error occurs.

I dug into the problem and found the way we calcuate approximate data size is pretty out-of-date. We can use table properties to get more accurate results.

Test Plan: ran ./table_test and passed

Reviewers: igor, dhruba, haobo, sdong

CC: leveldb

Differential Revision: https://reviews.facebook.net/D16509

table/block_based_table_reader.cc

@@ -1025,11 +1025,15 @@ uint64_t BlockBasedTable::ApproximateOffsetOf(const Slice& key) {
       result = rep_->metaindex_handle.offset();
     }
   } else {
-    // key is past the last key in the file.  Approximate the offset
-    // by returning the offset of the metaindex block (which is
-    // right near the end of the file).
+    // key is past the last key in the file. If table_properties is not
+    // available, approximate the offset by returning the offset of the
+    // metaindex block (which is right near the end of the file).
+    result = rep_->table_properties->data_size;
+    // table_properties is not present in the table.
+    if (result == 0) {
       result = rep_->metaindex_handle.offset();
     }
+  }
   return result;
 }