[IO] Removed a no-op setting the start of a buffer to itself when writing from an IO buffer.  All Parrot and Rakudo tests still pass.
[IO] Removed a no-op setting the start of a buffer to itself when writing from
an IO buffer.  All Parrot and Rakudo tests still pass.

git-svn-id: 6e74a02f85675cec270f5d931b0f6998666294a3@35903 d31e2699-5ff4-0310-a27c-f18f2fbe73fe

ashgti/parrot,ashgti/parrot,ashgti/parrot,ashgti/parrot,ashgti/parrot,ashgti/parrot,ashgti/parrot