chore: update stage0

This makes it easier to distinguish tests that are actually
failing while we work on the new codegen.

src/Init/Data/Vector/Extract.lean

@@ -9,6 +9,8 @@ prelude
 import Init.Data.Vector.Lemmas
 import Init.Data.Array.Extract
 
+set_option maxHeartbeats 20000000
+
 /-!
 # Lemmas about `Vector.extract`
 -/

src/Lean/CoreM.lean

@@ -658,7 +658,7 @@ private def checkUnsupported [Monad m] [MonadEnv m] [MonadError m] (decl : Decla
     | _ => pure ()
 
 register_builtin_option compiler.enableNew : Bool := {
-  defValue := false
+  defValue := true -- false
   group    := "compiler"
   descr    := "(compiler) enable the new code generator, this should have no significant effect on your code but it does help to test the new code generator; unset to only use the old code generator instead"
 }