chore: move tests to new frontend

tests/compiler/array_test2.lean

@@ -1,5 +1,6 @@
-def check (b : Bool) : IO Unit :=
-unless b $ IO.println "failed"
+#lang lean4
+def check (b : Bool) : IO Unit := do
+unless b do  IO.println "failed"
 
 
 def main : IO Unit :=

tests/compiler/strictAndOr.lean

@@ -1,3 +1,5 @@
+#lang lean4
+
 def main : IO Unit :=
 IO.println (strictOr false false) *>
 IO.println (strictOr false true) *>

tests/compiler/t1.lean

@@ -1,3 +1,4 @@
+#lang lean4
 def main (xs : List String) : IO UInt32 :=
 IO.println "hello world" *>
 pure 0

tests/lean/run/task_test_io.lean

@@ -1,27 +1,28 @@
-#eval do
-  t1 ← IO.asTask $ Nat.forM 10 fun _ => IO.println "hi";
-  t2 ← IO.asTask $ Nat.forM 10 fun _ => IO.println "ho";
+#lang lean4
+#eval id (α := IO _) do
+  let t1 ← IO.asTask $ Nat.forM 10 fun _ => IO.println "hi";
+  let t2 ← IO.asTask $ Nat.forM 10 fun _ => IO.println "ho";
   IO.ofExcept t1.get
 
-#eval do
-  t1 ← IO.mapTask IO.println (Task.spawn fun _ => "ha");
+#eval id (α := IO _) do
+  let t1 ← IO.mapTask IO.println (Task.spawn fun _ => "ha");
   pure ()
 
-#eval do
-  t1 ← IO.bindTask (Task.spawn fun _ => "hu") fun s =>
+#eval id (α := IO _) do
+  let t1 ← IO.bindTask (Task.spawn fun _ => "hu") fun s =>
     IO.asTask (IO.println s);
   pure ()
 
-#eval do
-  t1 ← IO.asTask do {
-    c ← IO.checkCanceled;
+#eval id (α := IO _) do
+  let t1 ← IO.asTask do {
+    let c ← IO.checkCanceled;
     IO.println (if c then "canceled!" else "done!")
   };
   pure ()
 
-#eval do
-  t1 ← IO.asTask do {
-    c ← IO.checkCanceled;
+#eval id (α := IO _) do
+  let t1 ← IO.asTask do {
+    let c ← IO.checkCanceled;
     IO.println (if c then "canceled! 2" else "done! 2")
   };
   IO.cancel t1;

tests/lean/run/update.lean

@@ -1,3 +1,4 @@
+#lang lean4
 import Lean.Expr
 open Lean