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/executor/wasmtime/src/tests.rs

@@ -17,7 +17,7 @@
 // along with this program. If not, see <https://www.gnu.org/licenses/>.
 
 use codec::{Decode as _, Encode as _};
-use sc_executor_common::{runtime_blob::RuntimeBlob, wasm_runtime::WasmModule};
+use sc_executor_common::{error::Error, runtime_blob::RuntimeBlob, wasm_runtime::WasmModule};
 use sc_runtime_test::wasm_binary_unwrap;
 use std::sync::Arc;
 
@@ -158,11 +158,13 @@ fn test_stack_depth_reaching() {
 	};
 	let mut instance = runtime.new_instance().expect("failed to instantiate a runtime");
 
-	let err = instance.call_export("test-many-locals", &[]).unwrap_err();
-
-	assert!(format!("{:?}", err).starts_with(
-		"Other(\"Wasm execution trapped: wasm trap: wasm `unreachable` instruction executed"
-	));
+	match instance.call_export("test-many-locals", &[]).unwrap_err() {
+		Error::AbortedDueToTrap(error) => {
+			let expected = "wasm trap: wasm `unreachable` instruction executed";
+			assert_eq!(error.message, expected);
+		},
+		error => panic!("unexpected error: {:?}", error),
+	}
 }
 
 #[test]