Dead bushes and vines drop with silk touch

Summary:
Dead bushes and vines drop with silk touch. No other plants (other than flowers, as they drop even without tools) drop when silk touch is used. Since MC-166084 has been resolved to work as intended, plants should not drop with silk touch.

Steps to reproduce:

1. Find/place a vine and a dead bush.
2. Enchant any tool with silk touch (except shears).
3. Try to break the dead bush and vine with the enchanted tool.

Observed results:
Dead bush and vine drops.

Expected results:
Dead bush and vine does not drop.