Don't check assert_trap tests when Lightbeam is enabled.

Lightbeam doesn't yet produce trap metadata, so it can't yet match the
expected `assert_trap` messages. Disable them for now.

wasmtime-wast/Cargo.toml

@@ -25,3 +25,6 @@ failure_derive = { version = "0.1.3", default-features = false }
 [badges]
 maintenance = { status = "experimental" }
 travis-ci = { repository = "CraneStation/wasmtime" }
+
+[features]
+lightbeam = []

wasmtime-wast/src/wast.rs

@@ -298,6 +298,12 @@ impl WastContext {
                             message: trap_message,
                         } => {
                             if !trap_message.contains(&message) {
+                                #[cfg(feature = "lightbeam")]
+                                println!(
+                                    "{}:{}: TODO: Check the assert_trap message: {}",
+                                    filename, line, message
+                                );
+                                #[cfg(not(feature = "lightbeam"))]
                                 return Err(WastFileError {
                                     filename: filename.to_string(),
                                     line,