Issue #6054: Do not normalize stored pathnames.

No longer use tarfile.normpath() on pathnames. Store pathnames
unchanged, i.e. do not remove "./", "../" and "//" occurrences.
However, still convert absolute to relative paths.
diff --git a/Misc/NEWS b/Misc/NEWS
index a63182f..49a0942 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -359,6 +359,8 @@
 Library
 -------
 
+- Issue #6054: Do not normalize stored pathnames in tarfile.
+
 - Issue #6794: Fix Decimal.compare_total and Decimal.compare_total_mag: NaN
   payloads are now ordered by integer value rather than lexicographically.