FindHeightsByCheckpoints finds the sealed height that produces the state commitment included in the checkpoint file.

GenerateProtocolSnapshotForCheckpoint finds a sealed block that produces the state commitment contained in the latest checkpoint file, and return a protocol snapshot for the finalized block that seals the sealed block.

GenerateProtocolSnapshotForCheckpointWithHeights does the same thing as GenerateProtocolSnapshotForCheckpoint except that it allows the caller to specify the end height of the sealed block that we iterate backwards from.