R1:f89f7086922c

Apply storage patches patch-by-patch, not database-by-database

Summary:
Ref T11044. Sometimes we have a sequence of patches like this:

- `01.newtable.sql`: Adds a new table to Files.
- `02.movedata.php`: Moves some data that used to live in Tokens to the new table.

This is fairly rare, but not unheard of. More commonly, we can have this sequence:

- `03.newtable.sql`: Add a new column to Phame.
- `04.setvalue.php`: Copy data into that new column.

In both cases, when applying database-by…