Add in-kernel test runner

This adds a way to run tests inside the Smalltown kernel.

Improvements to the Bazel part of this are tracked in T726

Test Plan: Tested by intentionally failing the test.

X-Origin-Diff: phab/D485
GitOrigin-RevId: e4aad7f28d122d82a7fcb6699e678cbe022e2f73
diff --git a/core/tools/ktestinit/BUILD.bazel b/core/tools/ktestinit/BUILD.bazel
new file mode 100644
index 0000000..74eb742
--- /dev/null
+++ b/core/tools/ktestinit/BUILD.bazel
@@ -0,0 +1,16 @@
+load("@io_bazel_rules_go//go:def.bzl", "go_binary", "go_library")
+
+go_library(
+    name = "go_default_library",
+    srcs = ["main.go"],
+    importpath = "git.monogon.dev/source/nexantic.git/core/tools/ktestinit",
+    visibility = ["//visibility:private"],
+    deps = ["@org_golang_x_sys//unix:go_default_library"],
+)
+
+go_binary(
+    name = "ktestinit",
+    embed = [":go_default_library"],
+    pure = "on",
+    visibility = ["//visibility:public"],
+)