Add test to fs.readFileSync in TypeScript files (#1736) (#2046)

---
name: Add test to fs.readFileSync in TypeScript files
---
```
parcel-bundler version 1.9.7
```

## 💥 Problem

Inlining file in browser mode doesn't work in TypeScript files when `fs` is imported with star import or default import. The only way to use `readFileSync` is:
```typescript
import { readFileSync } from 'fs';
const raw = readFileSync(__dirname + '/raw.tsx', 'utf-8');
```

### Reproduction: 
Repo: https://github.com/hasparus/parcel-readfilesync-typescript-repro
ghPages: https://hasparus.github.io/parcel-readfilesync-typescript-repro/
CodeSandbox: https://codesandbox.io/s/github/hasparus/parcel-readfilesync-typescript-repro/tree/master/

Fun Fact: All ways to import `fs` work on CodeSandbox (parcel template).

## ↪️ Pull Request
Adds test to `fs.readFileSync` in TypeScript files and thus provides better workaround for #1736.

## ✔️ PR Todo
- [X] Link in #1736.
- [X] Post reproduction to CodeSandbox.
- [ ] Document how to use `readFileSync` in TypeScript?

test/integration/typescript-fs/index.ts

@@ -0,0 +1,7 @@
+import { readFileSync } from 'fs';
+import rawFromTsx from './readFromTsx';
+
+module.exports = {
+  fromTs: readFileSync(__dirname + '/raw.tsx', "utf-8"),
+  fromTsx: rawFromTsx,
+};

test/integration/typescript-fs/raw.tsx

@@ -0,0 +1 @@
+export default <div>Hello</div>;

test/integration/typescript-fs/readFromTsx.tsx

@@ -0,0 +1,5 @@
+import { readFileSync } from 'fs';
+
+const raw = readFileSync(__dirname + '/raw.tsx', "utf-8");
+
+export default raw;

test/typescript.js

@@ -140,4 +140,18 @@ describe('typescript', function() {
     assert.equal(typeof output.test, 'function');
     assert.equal(output.test(), 'test passed');
   });
+
+  it('fs.readFileSync should inline a file as a string', async function() {
+    let b = await bundle(
+      path.join(__dirname, '/integration/typescript-fs/index.ts')
+    );
+
+    const text = 'export default <div>Hello</div>;';
+    let output = await run(b);
+
+    assert.deepEqual(output, {
+      fromTs: text,
+      fromTsx: text
+    });
+  });
 });