Update the massif/big-alloc test for ppc64*.
In comparison to the existing .exp files, the time,total,extra-heap
values generated on ppc64* vary from the other architectures.
This .exp allows the ppc64 targets to pass the test.
This patch fixes Vagrind bugzilla 347322.
git-svn-id: svn://svn.valgrind.org/valgrind/trunk@15226
