Remove Polkadot & Kusama native runtime (#1304)

This pull request removes the Polkadot and Kusama native runtime from
the polkadot node. This brings some implications with it:

There are no more kusama/polkadot-dev chain specs available. We will
need to write some tooling in the fellowship repo to provide them
easily.

The try-runtime job for polkadot & kusama is not available anymore as we
don't have the dev chain specs anymore.

Certain benchmarking commands will also not work until we migrate them
to use a runtime api.

Some crates in utils are still depending on the polkadot/kusama native
runtime that will also need to be fixed.

Port of: https://github.com/paritytech/polkadot/pull/7467

polkadot/node/test/service/src/chain_spec.rs

@@ -20,9 +20,7 @@ use babe_primitives::AuthorityId as BabeId;
 use grandpa::AuthorityId as GrandpaId;
 use pallet_staking::Forcing;
 use polkadot_primitives::{AccountId, AssignmentId, ValidatorId, MAX_CODE_SIZE, MAX_POV_SIZE};
-use polkadot_service::chain_spec::{
-	get_account_id_from_seed, get_from_seed, polkadot_chain_spec_properties, Extensions,
-};
+use polkadot_service::chain_spec::{get_account_id_from_seed, get_from_seed, Extensions};
 use polkadot_test_runtime::BABE_GENESIS_EPOCH_CONFIG;
 use sc_chain_spec::{ChainSpec, ChainType};
 use sp_authority_discovery::AuthorityId as AuthorityDiscoveryId;
@@ -36,6 +34,16 @@ const DEFAULT_PROTOCOL_ID: &str = "dot";
 pub type PolkadotChainSpec =
 	sc_service::GenericChainSpec<polkadot_test_runtime::RuntimeGenesisConfig, Extensions>;
 
+/// Returns the properties for the [`PolkadotChainSpec`].
+pub fn polkadot_chain_spec_properties() -> serde_json::map::Map<String, serde_json::Value> {
+	serde_json::json!({
+		"tokenDecimals": 10,
+	})
+	.as_object()
+	.expect("Map given; qed")
+	.clone()
+}
+
 /// Local testnet config (multivalidator Alice + Bob)
 pub fn polkadot_local_testnet_config() -> PolkadotChainSpec {
 	PolkadotChainSpec::from_genesis(