Wasm execution optimizations (#466)

* WASM execution optimizations

* Dropped min-heap-pages

* Fixed tests

* Fixed tests 2

polkadot/api/src/full.rs

@@ -200,7 +200,7 @@ mod tests {
 			timestamp: Some(Default::default()),
 		};
 
-		::client::new_in_mem(LocalDispatch::with_heap_pages(8, 8), genesis_config).unwrap()
+		::client::new_in_mem(LocalDispatch::with_heap_pages(8), genesis_config).unwrap()
 	}
 
 	#[test]

polkadot/parachain/Cargo.toml

@@ -6,7 +6,7 @@ description = "Types and utilities for creating and working with parachains"
 
 [dependencies]
 substrate-codec = { path = "../../substrate/codec", default-features = false }
-wasmi = { version = "0.3", optional = true }
+wasmi = { version = "0.4", optional = true }
 error-chain = { version = "0.12", optional = true }
 
 [dev-dependencies]