Make debug builds more usable (#4683)

* Make debug builds more usable

This pr makes debug builds more usable in terms of `cargo run -- --dev`.

1. `--dev` activates `--execution native`, iff `--execution` is not
given or no sub `--execution-*` is given.
2. It was probably a mistake to compile WASM in debug for a debug build.
So, we now build the WASM binary always as `release` (if not requested
differently by the user). So, we trade compilation time for a better
debug experience.

* Make sure we only overwrite default values

* Make it work

* Apply suggestion

substrate/bin/node/cli/src/cli.rs

@@ -141,7 +141,12 @@ pub fn run<I, T, E>(args: I, exit: E, version: sc_cli::VersionInfo) -> error::Re
 				&version,
 				None,
 			)?;
-			sc_cli::fill_import_params(&mut config, &cli_args.import_params, ServiceRoles::FULL)?;
+			sc_cli::fill_import_params(
+				&mut config,
+				&cli_args.import_params,
+				ServiceRoles::FULL,
+				cli_args.shared_params.dev,
+			)?;
 
 			match ChainSpec::from(config.chain_spec.id()) {
 				Some(ref c) if c == &ChainSpec::Development || c == &ChainSpec::LocalTestnet => {},