cmd/dist: enable testsanitizer test on ppc64le

cmd/dist: enable testsanitizer test on ppc64le

Even though the -race option works for ppc64le, some of the
testsanitizer test have failed in the past on our builders. These
same failures can't be reproduced on other systems.

This is an experiment to re-enable this test on ppc64le to see if
it still fails on the builders.

Updates #45040

Change-Id: I0729bec5864e6c4cc752968485e89179df027063
Reviewed-on: https://go-review.googlesource.com/c/go/+/424534
Run-TryBot: Lynn Boger <laboger@linux.vnet.ibm.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Reviewed-by: Archana Ravindar <aravind5@in.ibm.com>
Reviewed-by: Bryan Mills <bcmills@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>