test-bzr: portable shell and utf-8 strings for Mac OS

Make the shell script more portable:
- Split export X=Y into 2 lines
- Use printf instead of echo -e

Use UTF-8 code points which are not decomposed by the filesystem:
 Code points like "á" will be decomposed by Mac OS X.
 bzr is unable to find the file "á" on disk.
 Use code points from unicode which can not be decomposed.
 In other words, the precompsed form use the same bytes as decomposed.

Signed-off-by: Torsten Bögershausen <tboegi@web.de>
Acked-by: Felipe Contreras <felipe.contreras@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>