fix(tests/lean): adjust tests to reflect recent changes

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>

tests/lean/apply_tac_bug.lean

@@ -1,4 +1,3 @@
-import heq
 import macros
 import tactic
 
@@ -7,4 +6,3 @@ theorem my_proof_irrel {a b : Bool} (H1 : a) (H2 : b) : H1 == H2
        H1_eq_H1b : H1 == H1b             := hsymm (cast_heq (by simp) H1),
        H1b_eq_H2 : H1b == H2             := to_heq (proof_irrel H1b H2)
    in  htrans H1_eq_H1b H1b_eq_H2
-

tests/lean/apply_tac_bug.lean.expected.out

@@ -1,6 +1,5 @@
   Set: pp::colors
   Set: pp::unicode
-  Imported 'heq'
   Imported 'macros'
   Imported 'tactic'
   Proved: my_proof_irrel

tests/lean/eq3.lean

@@ -1,4 +1,3 @@
-import heq
 variable Vector : Nat -> Type
 variable n  : Nat
 variable v1 : Vector n

tests/lean/eq3.lean.expected.out

@@ -1,6 +1,5 @@
   Set: pp::colors
   Set: pp::unicode
-  Imported 'heq'
   Assumed: Vector
   Assumed: n
   Assumed: v1

tests/lean/simp20.lean

@@ -1,4 +1,3 @@
-import heq
 rewrite_set simple
 
 set_option pp::implicit true

tests/lean/simp20.lean.expected.out

@@ -1,6 +1,5 @@
   Set: pp::colors
   Set: pp::unicode
-  Imported 'heq'
   Set: lean::pp::implicit
   Assumed: g
   Assumed: B