Reduce size of TypeScript Compiler snapshot (#6809)

This PR is intentionally ugly. It duplicates all of the code in cli/js2/ into
cli/tsc/  ... because it's very important that we all understand that this code
is unnecessarily duplicated in our binary. I hope this ugliness provides the
motivation to clean it up.

The typescript git submodule is removed, because it's a very large repo and
contains all sorts of stuff we don't need. Instead the necessary files are
copied directly into the deno repo. Hence +200k lines.

COMPILER_SNAPSHOT.bin size
```
master         3448139
this branch    3320972
```

Fixes #6812

1 files changed, 154 insertions, 0 deletions

diff --git a/cli/tsc/06_util.js b/cli/tsc/06_util.js
new file mode 100644
index 000000000..086275bd8
--- /dev/null
+++ b/cli/tsc/06_util.js
@@ -0,0 +1,154 @@
+// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
+((window) => {
+  const { build } = window.__bootstrap.build;
+  const internals = window.__bootstrap.internals;
+  let logDebug = false;
+  let logSource = "JS";
+
+  function setLogDebug(debug, source) {
+    logDebug = debug;
+    if (source) {
+      logSource = source;
+    }
+  }
+
+  function log(...args) {
+    if (logDebug) {
+      // if we destructure `console` off `globalThis` too early, we don't bind to
+      // the right console, therefore we don't log anything out.
+      globalThis.console.log(`DEBUG ${logSource} -`, ...args);
+    }
+  }
+
+  class AssertionError extends Error {
+    constructor(msg) {
+      super(msg);
+      this.name = "AssertionError";
+    }
+  }
+
+  function assert(cond, msg = "Assertion failed.") {
+    if (!cond) {
+      throw new AssertionError(msg);
+    }
+  }
+
+  function createResolvable() {
+    let resolve;
+    let reject;
+    const promise = new Promise((res, rej) => {
+      resolve = res;
+      reject = rej;
+    });
+    promise.resolve = resolve;
+    promise.reject = reject;
+    return promise;
+  }
+
+  function notImplemented() {
+    throw new Error("not implemented");
+  }
+
+  function immutableDefine(
+    o,
+    p,
+    // eslint-disable-next-line @typescript-eslint/no-explicit-any
+    value,
+  ) {
+    Object.defineProperty(o, p, {
+      value,
+      configurable: false,
+      writable: false,
+    });
+  }
+
+  function pathFromURLWin32(url) {
+    const hostname = url.hostname;
+    const pathname = decodeURIComponent(url.pathname.replace(/\//g, "\\"));
+
+    if (hostname !== "") {
+      //TODO(actual-size) Node adds a punycode decoding step, we should consider adding this
+      return `\\\\${hostname}${pathname}`;
+    }
+
+    const validPath = /^\\(?<driveLetter>[A-Za-z]):\\/;
+    const matches = validPath.exec(pathname);
+
+    if (!matches?.groups?.driveLetter) {
+      throw new TypeError("A URL with the file schema must be absolute.");
+    }
+
+    // we don't want a leading slash on an absolute path in Windows
+    return pathname.slice(1);
+  }
+
+  function pathFromURLPosix(url) {
+    if (url.hostname !== "") {
+      throw new TypeError(`Host must be empty.`);
+    }
+
+    return decodeURIComponent(url.pathname);
+  }
+
+  function pathFromURL(pathOrUrl) {
+    if (pathOrUrl instanceof URL) {
+      if (pathOrUrl.protocol != "file:") {
+        throw new TypeError("Must be a file URL.");
+      }
+
+      return build.os == "windows"
+        ? pathFromURLWin32(pathOrUrl)
+        : pathFromURLPosix(pathOrUrl);
+    }
+    return pathOrUrl;
+  }
+
+  internals.exposeForTest("pathFromURL", pathFromURL);
+
+  function writable(value) {
+    return {
+      value,
+      writable: true,
+      enumerable: true,
+      configurable: true,
+    };
+  }
+
+  function nonEnumerable(value) {
+    return {
+      value,
+      writable: true,
+      configurable: true,
+    };
+  }
+
+  function readOnly(value) {
+    return {
+      value,
+      enumerable: true,
+    };
+  }
+
+  function getterOnly(getter) {
+    return {
+      get: getter,
+      enumerable: true,
+    };
+  }
+
+  window.__bootstrap.util = {
+    log,
+    setLogDebug,
+    notImplemented,
+    createResolvable,
+    assert,
+    AssertionError,
+    immutableDefine,
+    pathFromURL,
+    writable,
+    nonEnumerable,
+    readOnly,
+    getterOnly,
+  };
+})(this);