Parity: Cushions don't last so long as furnace fuel compared to Java

The bug:

Cushions don't last so long as furnace fuel compared to Java.

Steps to Repro:

1. Get a furnace

2. Get a stack of 16 cushions

3. Place the stack of cushions as furnace fuel

4. Place a wooden log as the ingredient

Observed Result:

4 cushions were consumed trying to smelt the log into charcoal, so cushions only smelt 0.25 items each.

Expected Result:

Only 1 cushion is consumed trying to smelt the log into charcoal, so cushions smelt 1 item each like Java.