test: refactor test-internal-errors

Use block-scoping rather than `err1`, `err2`, etc.

PR-URL: nodejs#15721
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Gibson Fahnestock <gibfahn@gmail.com>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

test/parallel/test-internal-errors.js

@@ -12,36 +12,45 @@ function invalidKey(key) {
 errors.E('TEST_ERROR_1', 'Error for testing purposes: %s');
 errors.E('TEST_ERROR_2', (a, b) => `${a} ${b}`);
 
-const err1 = new errors.Error('TEST_ERROR_1', 'test');
-const err2 = new errors.TypeError('TEST_ERROR_1', 'test');
-const err3 = new errors.RangeError('TEST_ERROR_1', 'test');
-const err4 = new errors.Error('TEST_ERROR_2', 'abc', 'xyz');
-const err5 = new errors.Error('TEST_ERROR_1');
-
-assert(err1 instanceof Error);
-assert.strictEqual(err1.name, 'Error [TEST_ERROR_1]');
-assert.strictEqual(err1.message, 'Error for testing purposes: test');
-assert.strictEqual(err1.code, 'TEST_ERROR_1');
-
-assert(err2 instanceof TypeError);
-assert.strictEqual(err2.name, 'TypeError [TEST_ERROR_1]');
-assert.strictEqual(err2.message, 'Error for testing purposes: test');
-assert.strictEqual(err2.code, 'TEST_ERROR_1');
-
-assert(err3 instanceof RangeError);
-assert.strictEqual(err3.name, 'RangeError [TEST_ERROR_1]');
-assert.strictEqual(err3.message, 'Error for testing purposes: test');
-assert.strictEqual(err3.code, 'TEST_ERROR_1');
-
-assert(err4 instanceof Error);
-assert.strictEqual(err4.name, 'Error [TEST_ERROR_2]');
-assert.strictEqual(err4.message, 'abc xyz');
-assert.strictEqual(err4.code, 'TEST_ERROR_2');
-
-assert(err5 instanceof Error);
-assert.strictEqual(err5.name, 'Error [TEST_ERROR_1]');
-assert.strictEqual(err5.message, 'Error for testing purposes: %s');
-assert.strictEqual(err5.code, 'TEST_ERROR_1');
+{
+  const err = new errors.Error('TEST_ERROR_1', 'test');
+  assert(err instanceof Error);
+  assert.strictEqual(err.name, 'Error [TEST_ERROR_1]');
+  assert.strictEqual(err.message, 'Error for testing purposes: test');
+  assert.strictEqual(err.code, 'TEST_ERROR_1');
+}
+
+{
+  const err = new errors.TypeError('TEST_ERROR_1', 'test');
+  assert(err instanceof TypeError);
+  assert.strictEqual(err.name, 'TypeError [TEST_ERROR_1]');
+  assert.strictEqual(err.message, 'Error for testing purposes: test');
+  assert.strictEqual(err.code, 'TEST_ERROR_1');
+}
+
+{
+  const err = new errors.RangeError('TEST_ERROR_1', 'test');
+  assert(err instanceof RangeError);
+  assert.strictEqual(err.name, 'RangeError [TEST_ERROR_1]');
+  assert.strictEqual(err.message, 'Error for testing purposes: test');
+  assert.strictEqual(err.code, 'TEST_ERROR_1');
+}
+
+{
+  const err = new errors.Error('TEST_ERROR_2', 'abc', 'xyz');
+  assert(err instanceof Error);
+  assert.strictEqual(err.name, 'Error [TEST_ERROR_2]');
+  assert.strictEqual(err.message, 'abc xyz');
+  assert.strictEqual(err.code, 'TEST_ERROR_2');
+}
+
+{
+  const err = new errors.Error('TEST_ERROR_1');
+  assert(err instanceof Error);
+  assert.strictEqual(err.name, 'Error [TEST_ERROR_1]');
+  assert.strictEqual(err.message, 'Error for testing purposes: %s');
+  assert.strictEqual(err.code, 'TEST_ERROR_1');
+}
 
 assert.throws(
   () => new errors.Error('TEST_FOO_KEY'),