bpo-30620: Remove dead lines from textwrap.dedent (GH-2064)

diff --git a/Lib/textwrap.py b/Lib/textwrap.py
index 0c18dc5..8103f34 100644
--- a/Lib/textwrap.py
+++ b/Lib/textwrap.py
@@ -450,8 +450,6 @@
                 if x != y:
                     margin = margin[:i]
                     break
-            else:
-                margin = margin[:len(indent)]
 
     # sanity check (testing/debugging only)
     if 0 and margin: