Correct the rolling checkpoint size for the current checkpoint's root page size, it shouldn't be included because it's an allocation that's not part of the next checkpoint.
The test/format program randomly generates WiredTiger databases with different configurations and different size objects and then does operations on those files. The goal is to test the WiredTiger file formats. test/format should be linked with a version of Berkeley DB (which it uses to verify format's results). Use the configuration option --with-berkeleydb=DIR to specify the top-level of an installed Berkeley DB distribution directory, for example: --with-berkeleydb=/usr/local/BerkeleyDB.5.3