Refactor processBlockPlace logic. Fixes BUKKIT-3406 and BUKKIT-3454

The previous logic was faulty since it lost the logic of "placing" the
block. It was also taking into account data that could have been
changed outside of the processing of this event, which is irrelevant
to the processing of this event.

src/main/java/net/minecraft/server/BlockPumpkin.java

@@ -40,7 +40,6 @@ public class BlockPumpkin extends BlockDirectional {
 
     public void onPlace(World world, int i, int j, int k) {
         super.onPlace(world, i, j, k);
-        if (world.suppressPhysics) return; // CraftBukkit
         if (world.getTypeId(i, j - 1, k) == Block.SNOW_BLOCK.id && world.getTypeId(i, j - 2, k) == Block.SNOW_BLOCK.id) {
             if (!world.isStatic) {
                 // CraftBukkit start - use BlockStateListPopulator