Add a new host function for reporting fatal errors; make WASM backtraces readable when printing out errors (#10741)

* Add a new host function for reporting fatal errors

* Fix one of the wasmtime executor tests

* Have `#[runtime_interface(wasm_only)]` actually mean WASM-only, and not no_std-only

* Print out errors through `Display` instead of `Debug`

* Switch one more trait to require `Error` for its error instead of only `Debug`

* Align to review comments

substrate/client/service/src/chain_ops/check_block.rs

@@ -46,6 +46,6 @@ where
 			import_blocks(client, import_queue, reader, true, true)
 		},
 		Ok(None) => Box::pin(future::err("Unknown block".into())),
-		Err(e) => Box::pin(future::err(format!("Error reading block: {:?}", e).into())),
+		Err(e) => Box::pin(future::err(format!("Error reading block: {}", e).into())),
 	}
 }

substrate/client/service/src/chain_ops/import_blocks.rs

@@ -322,7 +322,7 @@ where
 
 			for result in results {
 				if let (Err(err), hash) = result {
-					warn!("There was an error importing block with hash {:?}: {:?}", hash, err);
+					warn!("There was an error importing block with hash {:?}: {}", hash, err);
 					self.has_error = true;
 					break
 				}