Add test/async/dont-block-start.wast

Author: lukewagner

test/async/dont-block-start.wast

@@ -0,0 +1,21 @@
+(assert_trap
+  (component
+    (core module $Memory (memory (export "mem") 1))
+    (core instance $memory (instantiate $Memory))
+    (core module $M
+      (import "" "waitable-set.new" (func $waitable-set.new (result i32)))
+      (import "" "waitable-set.wait" (func $waitable-set.wait (param i32 i32) (result i32)))
+      (func $start
+        (drop (call $waitable-set.wait (call $waitable-set.new) (i32.const 0)))
+      )
+      (start $start)
+    )
+    (canon waitable-set.new (core func $waitable-set.new))
+    (canon waitable-set.wait (memory $memory "mem") (core func $waitable-set.wait))
+    (core instance $m (instantiate $M (with "" (instance
+      (export "waitable-set.new" (func $waitable-set.new))
+      (export "waitable-set.wait" (func $waitable-set.wait))
+    ))))
+  )
+  "cannot block a synchronous task before returning"
+)