bpo-42246: Partial implementation of PEP 626. (GH-23113)

* Implement new line number table format, as defined in PEP 626.
diff --git a/Lib/test/test_compile.py b/Lib/test/test_compile.py
index 6055192..0e06d11 100644
--- a/Lib/test/test_compile.py
+++ b/Lib/test/test_compile.py
@@ -155,8 +155,8 @@ def test_indentation(self):
     def test_leading_newlines(self):
         s256 = "".join(["\n"] * 256 + ["spam"])
         co = compile(s256, 'fn', 'exec')
-        self.assertEqual(co.co_firstlineno, 257)
-        self.assertEqual(co.co_lnotab, bytes())
+        self.assertEqual(co.co_firstlineno, 1)
+        self.assertEqual(list(co.co_lines()), [(0, 4, 257), (4, 8, None)])
 
     def test_literals_with_leading_zeroes(self):
         for arg in ["077787", "0xj", "0x.", "0e",  "090000000000000",