cmd/internal/testdir: pass -buildid to link command
The new dynamic loader in macOS 26 beta doesn't like binaries
without LC_UUID. Binaries built by "go build" have LC_UUID by
default. When invoking the linker manually, it has an LC_UUID by
default if a Go buildid is specified. This CL makes it pass
-buildid to link command for the test directory, so the binaries
will have LC_UUID.
Change-Id: I9369aeb7323d211eda80e4f22f459c220085f61d
Reviewed-on: https://go-review.googlesource.com/c/go/+/692876 Reviewed-by: David Chase <drchase@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>