EBLOB_AUTO_INDEXSORT eblob flag

New EBLOB_AUTO_INDEXSORT flag which enables sorting blob's index after the blob is closed. Extended running eblob_stress with EBLOB_AUTO_INDEXSORT flag.

Also added stat_file_time and stat_file_error to json statistics which can be used for determining hardware issues.
Binlog keeps removed keys that were removed from the blob while binlog was enabled. This is just sanity check that binlog contains only existent in index keys. It is uncommon case, so debug is improper level I will change it to error.