[dev.regabi] test: enable finalizer tests on !amd64

The gc implementation has had precise GC for a while now, so we can
enable these tests more broadly.

Confirmed that they still fail with gccgo 10.2.1.

Change-Id: Ic1c0394ab832024a99e34163c422941a3706e1a2
Reviewed-on: https://go-review.googlesource.com/c/go/+/281542


Trust: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>