mask necessary whitespace policy violations in test scripts

mask necessary whitespace policy violations in test scripts

All of these violations are necessary parts of the tests
(which are generally checking the behavior of trailing
whitespace, or contain diff fragments with empty lines).

Our solution is two-fold:

  1. Process input with whitespace problems using tr. This
     has the added bonus that it becomes very obvious where
     the bogus whitespace is intended to go.

  2. Move large diff fragments into their own supplemental
     files. This gets rid of the whitespace problem, since
     supplemental files are not checked, and it also makes
     the test script a bit easier to read.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>