Damage from fire blocks is calculated as if the fire was a full block

The Bug:

Relates to MC-150455.

Whether or not you are affected by fire is always calculated as if the fire were a full block. This means that fire on the side or bottom of a block can damage the player further away than its hitbox.

Steps to Reproduce:

1. Place any flammable block, for example an oak log.

2. Set fire to the side of the block using a flint and steel.

3. Put yourself into survival mode and walk into the block.

4. Walk slowly away from it.
   ❌ It will still set you on fire and damage you in even though it does not look like you are touching it.