tests: unify test-diff-newlines

tests/test-diff-newlines.t

@@ -1,8 +1,18 b''
-#!/bin/sh
+  $ hg init
+
+  $ python -c 'print "confuse str.splitlines\nembedded\rnewline"' > a
+  $ hg ci -Ama -d '1 0'
+  adding a
+
+  $ echo clean diff >> a
+  $ hg ci -mb -d '2 0'
 
-hg init
-python -c 'print "confuse str.splitlines\nembedded\rnewline"' > a
-hg ci -Ama -d '1 0'
-echo clean diff >> a
-hg ci -mb -d '2 0'
-hg diff -r0 -r1
+  $ hg diff -r0 -r1
+  diff -r 107ba6f817b5 -r 310ce7989cdc a
+  --- a/a	Thu Jan 01 00:00:01 1970 +0000
+  +++ b/a	Thu Jan 01 00:00:02 1970 +0000
+  @@ -1,2 +1,3 @@
+   confuse str.splitlines
+   embedded
+newline
+  +clean diff