sweet: disable code on aix and plan9 to fix builds

blevesearch's dependencies don't build on AIX or plan9.
gopher-lua's dependencies don't build on plan9.

Fixes #49920.
Fixes #49919.

Change-Id: Ia8ef5b27784db26e77d5769e606beddcac5e782a
Reviewed-on: https://go-review.googlesource.com/c/benchmarks/+/368754
Trust: Michael Knyszek <mknyszek@google.com>
Run-TryBot: Michael Knyszek <mknyszek@google.com>
Reviewed-by: Bryan Mills <bcmills@google.com>
7 files changed