In fixBug20757.php:

In fixBug20757.php:
* Don't use buildLike() just yet, for easy backporting to wmf-deployment.
* Don't try to fetch old_flags=object,external rows
* Skip rows with the wrong class using a MySQL condition since we really don't care about them
* Propagate old_flags to the new pointer row. This could be necessary if moveToExternal.php was run after compressOld.php from MW>1.5. This never actually happened at Wikimedia.
* Don't skip rows with bt_moved=0, we need to resolve these stubs if RCT is to continue.
* Fix isUnbrokenStub() to not overwrite its input, fixes minor progress message issue
* Tested locally.

In resolveStubs.php:
* Fixed two bugs in the condition intended to limit the rows acted on to HistoryBlobStub: the string we compared against was not all in lower case, and the character set was binary, making LOWER() do nothing.
* Resolve stubs with old_flags='object,utf-8', analysis showed that we have some of these on enwiki
* Tested locally.

In trackBlobs.php:
* Fixed a bug causing incorrect values to be inserted into bt_cgz_hash. There was no impact on RCT or any other script since bt_cgz_hash is unused at present. Tested locally.