Revert "Don't update snapshot blockstates" (Fixes #1882)

CraftBukkit already checks that we're not trying to copy data
back to the same snapshot, reverting this fixes the ability to
properly update non-snapshot blockstates

Spigot-Server-Patches/Add-sun-related-API.patch

@@ -17,7 +17,7 @@ index ee5078370..3059682a4 100644
          if (this.world.L() && !this.world.isClientSide) {
              float f = this.az();
 diff --git a/src/main/java/net/minecraft/server/World.java b/src/main/java/net/minecraft/server/World.java
-index 21cfcb50d..5a447f8ef 100644
+index 2e48ea9d8..a21de9b3d 100644
 --- a/src/main/java/net/minecraft/server/World.java
 +++ b/src/main/java/net/minecraft/server/World.java
 @@ -0,0 +0,0 @@ public abstract class World implements IEntityAccess, GeneratorAccess, IIBlockAc