WASM executor: add OutputExceedsBounds variant to Error (#13841)

* WASM executor: add `OutputExceedsBounds` variant to `Error`

Previously this was a `WasmError`, which is intended for runtime construction errors. However this
led to confusion as output-exceeds-bounds occurs due to execution of `validate_block`.

* Fix warning

substrate/client/executor/common/src/error.rs

@@ -104,6 +104,9 @@ pub enum Error {
 
 	#[error("Execution aborted due to trap: {0}")]
 	AbortedDueToTrap(MessageWithBacktrace),
+
+	#[error("Output exceeds bounds of wasm memory")]
+	OutputExceedsBounds,
 }
 
 impl wasmi::HostError for Error {}
@@ -153,7 +156,7 @@ pub enum WasmError {
 	Instantiation(String),
 
 	/// Other error happenend.
-	#[error("{0}")]
+	#[error("Other error happened while constructing the runtime: {0}")]
 	Other(String),
 }