Revert "Introduce and enforce block time (#232)" (#233)

This reverts commit ad392a0ef0.

substrate/polkadot/api/src/full.rs

@@ -221,7 +221,6 @@ mod tests {
 			democracy: Some(Default::default()),
 			parachains: Some(Default::default()),
 			staking: Some(Default::default()),
-			timestamp: Some(Default::default()),
 		};
 
 		::client::new_in_mem(LocalDispatch::new(), genesis_config.build_storage()).unwrap()