Planar dice cost resets after planeswalking

In a game with the Planechase option enabled, after a player has planeswalked, the incremental cost of rolling the planar dice resets to 0.
Instead, the cost should continue increasing after each dice a player rolls on a given turn.

Reproduce the issue in a game with Planechase enabled by rolling the planar die, planeswalking, and rolling again on the same turn. Trace the Planechase and planar-dice cost handling, then verify that the incremental cost continues increasing after planeswalking instead of resetting to 0.

Written by the indexing model from the issue text.