Remove system parachains Polkadot and Kusama runtimes (#1737)

Since the Polkadot and Kusama runtimes are no longer in the repo, the
relevant systems parachains runtimes also need to be removed. More
context [here](https://github.com/paritytech/polkadot-sdk/issues/603)
and [here](https://github.com/paritytech/polkadot-sdk/pull/1731).

Removes the following:
- `asset-hub-kusama` and `asset-hub-polkadot`
- `bridge-hub-kusama` and `bridge-hub-polkadot`
- `collectives-polkadot`
- `glutton-kusama`

Partially solves #603 and adds to #1731.

cumulus/polkadot-parachain/tests/benchmark_storage_works.rs

@@ -24,7 +24,7 @@ use std::{
 use tempfile::tempdir;
 
 /// The runtimes that this command supports.
-static RUNTIMES: [&str; 3] = ["asset-hub-westend", "asset-hub-kusama", "asset-hub-polkadot"];
+static RUNTIMES: [&str; 1] = ["asset-hub-westend"];
 
 /// The `benchmark storage` command works for the dev runtimes.
 #[test]