some zstd tests are breaking in ppc64le because it defines the max
number of supported cores as 128 (ZSTDMT_NBTHREADS_MAX 128) but the
Alpine ppc64le machine has 160 cores.
I am increasing the max core value to 256 for now and opened a bug[1]
in zstd project.
[1] https://github.com/facebook/zstd/issues/760