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, 84 insertions, 0 deletions

diff --git a/cli/tsc/10_dispatch_json.js b/cli/tsc/10_dispatch_json.js
new file mode 100644
index 000000000..3d19ea62a
--- /dev/null
+++ b/cli/tsc/10_dispatch_json.js
@@ -0,0 +1,84 @@
+// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
+((window) => {
+  const core = window.Deno.core;
+  const util = window.__bootstrap.util;
+  const getErrorClass = window.__bootstrap.errors.getErrorClass;
+  // Using an object without a prototype because `Map` was causing GC problems.
+  const promiseTable = Object.create(null);
+  let _nextPromiseId = 1;
+
+  function nextPromiseId() {
+    return _nextPromiseId++;
+  }
+
+  function decode(ui8) {
+    return JSON.parse(core.decode(ui8));
+  }
+
+  function encode(args) {
+    return core.encode(JSON.stringify(args));
+  }
+
+  function unwrapResponse(res) {
+    if (res.err != null) {
+      throw new (getErrorClass(res.err.kind))(res.err.message);
+    }
+    util.assert(res.ok != null);
+    return res.ok;
+  }
+
+  function asyncMsgFromRust(resUi8) {
+    const res = decode(resUi8);
+    util.assert(res.promiseId != null);
+
+    const promise = promiseTable[res.promiseId];
+    util.assert(promise != null);
+    delete promiseTable[res.promiseId];
+    promise.resolve(res);
+  }
+
+  function sendSync(
+    opName,
+    args = {},
+    ...zeroCopy
+  ) {
+    util.log("sendSync", opName);
+    const argsUi8 = encode(args);
+    const resUi8 = core.dispatchByName(opName, argsUi8, ...zeroCopy);
+    util.assert(resUi8 != null);
+    const res = decode(resUi8);
+    util.assert(res.promiseId == null);
+    return unwrapResponse(res);
+  }
+
+  async function sendAsync(
+    opName,
+    args = {},
+    ...zeroCopy
+  ) {
+    util.log("sendAsync", opName);
+    const promiseId = nextPromiseId();
+    args = Object.assign(args, { promiseId });
+    const promise = util.createResolvable();
+    const argsUi8 = encode(args);
+    const buf = core.dispatchByName(opName, argsUi8, ...zeroCopy);
+    if (buf != null) {
+      // Sync result.
+      const res = decode(buf);
+      promise.resolve(res);
+    } else {
+      // Async result.
+      promiseTable[promiseId] = promise;
+    }
+
+    const res = await promise;
+    return unwrapResponse(res);
+  }
+
+  window.__bootstrap.dispatchJson = {
+    asyncMsgFromRust,
+    sendSync,
+    sendAsync,
+  };
+})(this);