Makes all.bash work after echo 4 >/proc/cpu/alignment,
which means kill the process on an unaligned access.

The default behavior on DreamPlug/GuruPlug/SheevaPlug
is to simulate an ARMv3 and just let the unaligned accesses
stop at the word boundary, resulting in all kinds of surprises.

Fixes #1240.

R=ken2
CC=golang-dev
https://golang.org/cl/4551064