hdl: remove Repl per RFC 10.

Closes #770.

tests/test_hdl_ast.py

@@ -970,27 +970,6 @@ class CatTestCase(FHDLTestCase):
         self.assertEqual(a.signed, False)
 
 
-class ReplTestCase(FHDLTestCase):
-    @_ignore_deprecated
-    def test_cast(self):
-        r = Repl(0, 3)
-        self.assertEqual(repr(r), "(cat (const 1'd0) (const 1'd0) (const 1'd0))")
-
-    @_ignore_deprecated
-    def test_int_01(self):
-        with warnings.catch_warnings():
-            warnings.filterwarnings(action="error", category=SyntaxWarning)
-            Repl(0, 3)
-            Repl(1, 3)
-
-    @_ignore_deprecated
-    def test_int_wrong(self):
-        with self.assertWarnsRegex(SyntaxWarning,
-                r"^Value argument of Repl\(\) is a bare integer 2 used in bit vector context; "
-                r"consider specifying explicit width using C\(2, 2\) instead$"):
-            Repl(2, 3)
-
-
 class ArrayTestCase(FHDLTestCase):
     def test_acts_like_array(self):
         a = Array([1,2,3])