Use correct function name to PyArg_ParseTuple("is_package").

Fix off-by-1 error in normalize_line_endings():
  when *p == '\0' the NUL was copied into q and q was auto-incremented,
  the loop was broken out of,
  then a newline was appended followed by a NUL.
  So the function, in effect, was strcpy() but added two extra chars
  which was caught by obmalloc in debug mode, since there was only
  room for 1 additional newline.

Get test working under regrtest (added test_main).
diff --git a/Lib/test/test_zipimport.py b/Lib/test/test_zipimport.py
index 3c9457f..c9aff4a 100644
--- a/Lib/test/test_zipimport.py
+++ b/Lib/test/test_zipimport.py
@@ -186,6 +186,9 @@
     compression = ZIP_DEFLATED
 
 
-if __name__ == "__main__":
+def test_main():
     test_support.run_unittest(UncompressedZipImportTestCase)
     test_support.run_unittest(CompressedZipImportTestCase)
+
+if __name__ == "__main__":
+    test_main()