Minor test cleanup (GH-837) (GH-839)

* Remove unused test file

* Remove duplicated text in sndhdrdata README

(cherry picked from commit b8a7daf)

Author: zware

Lib/test/185test.db

@@ -3,10 +3,3 @@ following commands:
 
    dd if=/dev/zero of=sndhdr.raw bs=20 count=1
    sox -s -2 -c 2 -r 44100 sndhdr.raw sndhdr.<format>
-
-Sound file samples used by Lib/test/test_sndhdr.py and generated using the
-following commands:
-
-   dd if=/dev/zero of=sndhdr.raw bs=20 count=1
-   sox -s -2 -c 2 -r 44100 sndhdr.raw sndhdr.<format>
-