Dispenser Primed TNT Kills Sulfur Cube

TNT primed by dispenser kills Sulfur Cube with block in it.

Steps to reproduce the issue:

1. Place dispenser and put TNT into dispenser

2. Spawn Sulfur Cube near dispenser and give it a block

3. Activate dispenser with Redstone

Expected result:

Sulfur cube is launched based off of block and amount of damage, like with TNT primed by player.

Actual result:

Sulfur Cube dies and is split into baby Sulfur Cubes.