remove use of buildomat

.github/buildomat/config.toml

@@ -1,5 +0,0 @@
-#
-# This file, with this flag, must be present in the default branch in order for
-# the buildomat integration to create check suites.
-#
-enable = true

.github/buildomat/jobs/build-and-test.sh

@@ -1,19 +0,0 @@
-#!/bin/bash
-#:
-#: name = "build-and-test / illumos"
-#: variety = "basic"
-#: target = "helios"
-#: rust_toolchain = "stable"
-#:
-
-set -o errexit
-set -o pipefail
-set -o xtrace
-
-rustc --version
-
-banner build
-ptime -m cargo build --tests --verbose
-
-banner test
-ptime -m cargo test --verbose