Add More Logging to track total_log_size

Summary: We saw instances where total_log_size is off the real value, but I'm not able to reproduce it. Add more logging to help debugging when it happens again.

Test Plan: Run the unit test and see the logging.

Reviewers: andrewkr, yhchiang, igor, IslamAbdelRahman

Reviewed By: IslamAbdelRahman

Subscribers: leveldb, andrewkr, dhruba

Differential Revision: https://reviews.facebook.net/D60081

HISTORY.md

@@ -2,7 +2,7 @@
 ## Unreleased
 ### Public API Change
 * options.memtable_prefix_bloom_bits changes to options.memtable_prefix_bloom_bits_ratio and deprecate options.memtable_prefix_bloom_probes
-* enum type #movebot Rocksdb Users Group and PerfLevel changes from char to unsigned char. Value of all PerfLevel shift by one.
+* enum type CompressionType and PerfLevel changes from char to unsigned char. Value of all PerfLevel shift by one.
 * Deprecate options.filter_deletes.
 
 ### New Features