cl: compile async functions

cl/_testdata/async/in.go

@@ -0,0 +1,37 @@
+package async_compile
+
+import (
+	"fmt"
+
+	"github.com/goplus/llgo/x/async"
+)
+
+func GenInts() (co *async.Promise[int]) {
+	co.Yield(1)
+	co.Yield(2)
+	co.Yield(3)
+	return
+}
+
+func WrapGenInts() *async.Promise[int] {
+	return GenInts()
+}
+
+func UseGenInts() int {
+	co := WrapGenInts()
+	r := 0
+	for !co.Done() {
+		r += co.Next()
+	}
+	return r
+}
+
+func GenIntsWithDefer() (co *async.Promise[int]) {
+	defer func() {
+		if r := recover(); r != nil {
+			fmt.Println("panic:", r)
+		}
+	}()
+	co.Yield(1)
+	panic("GenIntsWithDefer")
+}