Name all the tasks! (#6726)

* Remove any implementation of `Spawn` or `Executor` from our task executors

* Fix compilation

* Rename `SpawnBlockingExecutor`

* Update primitives/core/src/traits.rs

Co-authored-by: Kian Paimani <5588131+kianenigma@users.noreply.github.com>

* Fix tests

Co-authored-by: Kian Paimani <5588131+kianenigma@users.noreply.github.com>

substrate/primitives/api/test/tests/runtime_calls.rs

@@ -197,11 +197,11 @@ fn record_proof_works() {
 		None,
 		8,
 	);
-	execution_proof_check_on_trie_backend::<_, u64, _>(
+	execution_proof_check_on_trie_backend::<_, u64, _, _>(
 		&backend,
 		&mut overlay,
 		&executor,
-		sp_core::tasks::executor(),
+		sp_core::testing::TaskExecutor::new(),
 		"Core_execute_block",
 		&block.encode(),
 		&runtime_code,