build: rewrite tools/ scripts to deno (#8247)

This commit rewrites scripts in "tools/" directory
to use Deno instead of Python. In return it allows 
to remove huge number of Python packages in "third_party/".

tools/format.js

@@ -0,0 +1,63 @@
+#!/usr/bin/env -S deno run --unstable --allow-write --allow-read --allow-run
+// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+import { getPrebuiltToolPath, getSources, join, ROOT_PATH } from "./util.js";
+
+async function dprint() {
+  const execPath = getPrebuiltToolPath("dprint");
+  console.log("dprint");
+  const p = Deno.run({
+    cmd: [execPath, "fmt"],
+  });
+  const { success } = await p.status();
+  if (!success) {
+    throw new Error("dprint failed");
+  }
+  p.close();
+}
+
+async function rustfmt() {
+  const configFile = join(ROOT_PATH, ".rustfmt.toml");
+  const sourceFiles = await getSources(ROOT_PATH, ["*.rs"]);
+
+  if (!sourceFiles.length) {
+    return;
+  }
+
+  console.log(`rustfmt ${sourceFiles.length} file(s)`);
+  const p = Deno.run({
+    cmd: ["rustfmt", "--config-path=" + configFile, "--", ...sourceFiles],
+  });
+  const { success } = await p.status();
+  if (!success) {
+    throw new Error("rustfmt failed");
+  }
+  p.close();
+}
+
+async function main() {
+  await Deno.chdir(ROOT_PATH);
+  await dprint();
+  await rustfmt();
+
+  if (Deno.args.includes("--check")) {
+    const git = Deno.run({
+      cmd: ["git", "status", "-uno", "--porcelain", "--ignore-submodules"],
+      stdout: "piped",
+    });
+
+    const { success } = await git.status();
+    if (!success) {
+      throw new Error("git status failed");
+    }
+    const out = new TextDecoder().decode(await git.output());
+    git.close();
+
+    if (out) {
+      console.log("run tools/format.js");
+      console.log(out);
+      Deno.exit(1);
+    }
+  }
+}
+
+await main();