fix(node): add missing process.reallyExit method (#19326)

This PR adds the missing `process.reallyExit()` method to node's
`process` object.

Was [pinged on
twitter](https://twitter.com/biwanczuk/status/1663326659787862017)
regarding running the `fastify` test suite in node. They use `node-tap`
which has been around arguably the longest of the test frameworks and
relies on a couple of old APIs. They have `signal-exit` as a dependency
which in turn [makes use of
`process.reallyExit()`](8fa7fc9a9c/src/index.ts (L19)).
That function cannot be found anywhere in their documentation, but
exists at runtime. See
6a6b3c5402/lib/internal/bootstrap/node.js (L172)

This doesn't yet make `node-tap` work, but gets us one step closer.

cli/tests/unit_node/process_test.ts

@@ -727,3 +727,22 @@ Deno.test({
     assertEquals(stripColor(decoder.decode(stdout).trim()), "exit");
   },
 });
+
+Deno.test({
+  name: "process.reallyExit",
+  async fn() {
+    const command = new Deno.Command(Deno.execPath(), {
+      args: [
+        "run",
+        "--quiet",
+        "--unstable",
+        "./testdata/process_really_exit.ts",
+      ],
+      cwd: testDir,
+    });
+    const { stdout } = await command.output();
+
+    const decoder = new TextDecoder();
+    assertEquals(stripColor(decoder.decode(stdout).trim()), "really exited");
+  },
+});

cli/tests/unit_node/testdata/process_really_exit.ts

@@ -0,0 +1,10 @@
+import process from "node:process";
+
+//deno-lint-ignore no-undef
+// @ts-ignore - Node typings don't even have this because it's
+// been deprecated for 4 years. But it's used in `signal-exit`,
+// which in turn is used in `node-tap`.
+process.reallyExit = function () {
+  console.info("really exited");
+};
+process.exit();