Better handling of stable-only build (#6569)

* Better handling of stable-only build

* Fix node template build

* Fix wasm builder node-template version mismatch

* Fix load_spec error

* Add , in parameter

* Add descrptive panic messages in tests

* Add descriptive tests in node/executor benches

* Fix missing compact_code_unwrap

* Add missing wasm_binary_unwrap function for executor integration test

* Only define import_sp_io in no_std

* Small Cargo.toml styling fix

* Bump wasm-builder to 2.0.0

* Fix all `with_wasm_builder_from_crates` version in Substrate

* Use `with_wasm_builder_from_crates` for node-template

Co-authored-by: Gavin Wood <gavin@parity.io>

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

@@ -25,7 +25,7 @@ use node_runtime::{
 	AuthorityDiscoveryConfig, BabeConfig, BalancesConfig, ContractsConfig, CouncilConfig,
 	DemocracyConfig,GrandpaConfig, ImOnlineConfig, SessionConfig, SessionKeys, StakerStatus,
 	StakingConfig, ElectionsConfig, IndicesConfig, SocietyConfig, SudoConfig, SystemConfig,
-	TechnicalCommitteeConfig, WASM_BINARY,
+	TechnicalCommitteeConfig, wasm_binary_unwrap,
 };
 use node_runtime::Block;
 use node_runtime::constants::currency::*;
@@ -241,7 +241,7 @@ pub fn testnet_genesis(
 
 	GenesisConfig {
 		frame_system: Some(SystemConfig {
-			code: WASM_BINARY.to_vec(),
+			code: wasm_binary_unwrap().to_vec(),
 			changes_trie_config: Default::default(),
 		}),
 		pallet_balances: Some(BalancesConfig {