Make test scripts more portable by detecting echo line-ending features, using

Make test scripts more portable by detecting echo line-ending features, using
fewer options for sed, and using a perl script for hexdump.  As a side effect,
hexdumps are more accurate (the hexdump util put * for as many multiples as
were output, whereas the perl script outputs a line for every byte, no matter
what).

svn path=/trunk/yasm/; revision=736