Manually consolidate the remaining ppc64/ppc64le test which
are not so trivial to automatically merge.

The remaining ppc64le tests are limited to cases where load/stores are
merged (this only happens on ppc64le) and the race detector (only
supported on ppc64le).

Change-Id: I1f9c0f3d3ddbb7fbbd8c81fbbd6537394fba63ce
Reviewed-on: https://go-review.googlesource.com/c/go/+/463217


Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Run-TryBot: Paul Murphy <murp@ibm.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Lynn Boger <laboger@linux.vnet.ibm.com>