bpo-42246: Don't forget the entry block when ensuring that all exits have a line number (GH-23636)

Don't forget the entry block when ensuring that all exits have a line number.
diff --git a/Python/importlib_external.h b/Python/importlib_external.h
index c459bcf..8f18d20 100644
--- a/Python/importlib_external.h
+++ b/Python/importlib_external.h
@@ -1153,7 +1153,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     0,169,2,114,123,0,0,0,114,191,0,0,0,114,7,0,
     0,0,114,7,0,0,0,114,8,0,0,0,218,13,99,114,
     101,97,116,101,95,109,111,100,117,108,101,55,3,0,0,115,
-    4,0,0,0,4,128,255,128,122,27,95,76,111,97,100,101,
+    4,0,0,0,4,0,255,128,122,27,95,76,111,97,100,101,
     114,66,97,115,105,99,115,46,99,114,101,97,116,101,95,109,
     111,100,117,108,101,99,2,0,0,0,0,0,0,0,0,0,
     0,0,3,0,0,0,5,0,0,0,67,0,0,0,115,56,
@@ -1292,7 +1292,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     32,32,32,78,114,7,0,0,0,41,3,114,123,0,0,0,
     114,52,0,0,0,114,37,0,0,0,114,7,0,0,0,114,
     7,0,0,0,114,8,0,0,0,114,232,0,0,0,105,3,
-    0,0,115,4,0,0,0,4,128,255,128,122,21,83,111,117,
+    0,0,115,4,0,0,0,4,0,255,128,122,21,83,111,117,
     114,99,101,76,111,97,100,101,114,46,115,101,116,95,100,97,
     116,97,99,2,0,0,0,0,0,0,0,0,0,0,0,5,
     0,0,0,10,0,0,0,67,0,0,0,115,70,0,0,0,
@@ -2019,7 +2019,7 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
     0,115,4,0,0,0,100,1,83,0,114,217,0,0,0,114,
     7,0,0,0,114,218,0,0,0,114,7,0,0,0,114,7,
     0,0,0,114,8,0,0,0,114,219,0,0,0,217,4,0,
-    0,115,4,0,0,0,4,128,255,128,122,30,95,78,97,109,
+    0,115,4,0,0,0,4,0,255,128,122,30,95,78,97,109,
     101,115,112,97,99,101,76,111,97,100,101,114,46,99,114,101,
     97,116,101,95,109,111,100,117,108,101,99,2,0,0,0,0,
     0,0,0,0,0,0,0,2,0,0,0,1,0,0,0,67,