reduce size of TypeType from 32bytes to 16bytes (vercel#4650)

### Description

saving some memory

Author: sokra

crates/turbo-tasks-memory/src/task.rs

@@ -79,18 +79,19 @@ struct ReadScopeCollectiblesTaskType {
 
 /// Different Task types
 enum TaskType {
+    // Note: double boxed to reduce TaskType size
     /// A root task that will track dependencies and re-execute when
     /// dependencies change. Task will eventually settle to the correct
     /// execution.
-    Root(NativeTaskFn),
+    Root(Box<NativeTaskFn>),
 
-    // TODO implement these strongly consistency
+    // Note: double boxed to reduce TaskType size
     /// A single root task execution. It won't track dependencies.
     /// Task will definitely include all invalidations that happened before the
     /// start of the task. It may or may not include invalidations that
     /// happened after that. It may see these invalidations partially
     /// applied.
-    Once(OnceTaskFn),
+    Once(Box<OnceTaskFn>),
 
     /// A task that reads all collectibles of a certain trait from a
     /// [TaskScope]. It will do that by recursively calling
@@ -540,7 +541,7 @@ impl Task {
         functor: impl Fn() -> NativeTaskFuture + Sync + Send + 'static,
         stats_type: StatsType,
     ) -> Self {
-        let ty = TaskType::Root(Box::new(functor));
+        let ty = TaskType::Root(Box::new(Box::new(functor)));
         let description = Self::get_event_description_static(id, &ty);
         Self {
             id,
@@ -559,7 +560,7 @@ impl Task {
         functor: impl Future<Output = Result<RawVc>> + Send + 'static,
         stats_type: StatsType,
     ) -> Self {
-        let ty = TaskType::Once(Mutex::new(Some(Box::pin(functor))));
+        let ty = TaskType::Once(Box::new(Mutex::new(Some(Box::pin(functor)))));
         let description = Self::get_event_description_static(id, &ty);
         Self {
             id,