fix(tests/lean): subtype notation is not in the top-level anymore

tests/lean/630.lean

@@ -1,5 +1,5 @@
 import data.pnat
-open pnat
+open pnat subtype
 
 print pnat
 

tests/lean/print_ax1.lean

@@ -1 +1,2 @@
+open subtype
 print axioms

tests/lean/print_ax2.lean

@@ -1 +1 @@
-print axioms
+open subtype print axioms

tests/lean/print_ax3.lean

@@ -1,3 +1,4 @@
+open subtype
 theorem foo1 : 0 = (0:num) :=
 rfl
 

tests/lean/run/sub_bug.lean

@@ -1,3 +1,3 @@
 import data.nat
-open nat
+open nat subtype
 check { x : nat | x > 0}

tests/lean/subpp.lean

@@ -1,4 +1,4 @@
 -- import data.subtype
-open nat
+open nat subtype
 
 check {x : nat| x > 0 }

tests/lean/subst_bug.lean

@@ -1,4 +1,4 @@
-example (f : nat → nat) (a b : nat) : f a = a → f (f a) = a :=
+open subtype example (f : nat → nat) (a b : nat) : f a = a → f (f a) = a :=
 begin
   intro h₁,
   subst h₁ -- ERROR