Show #blocks compressed and not compressed

For: facebook#1474
Helps show when the 12.5% threshold for GoodCompressionRatio (originally from ldb) is hit.

tools/sst_dump_tool_imp.h

@@ -46,7 +46,8 @@ class SstFileDumper {
                              RandomAccessFileReader* file, uint64_t file_size);
 
   uint64_t CalculateCompressedTableSize(const TableBuilderOptions& tb_options,
-                                        size_t block_size);
+                                        size_t block_size,
+                                        uint64_t& num_data_blocks);
 
   Status SetTableOptionsByMagicNumber(uint64_t table_magic_number);
   Status SetOldTableOptions();