fix: Fix the compiler test, and check if it worked. (#6638)

* Add tsick.js to rewrite enums.

tsc generates JavaScript which is incompatible with the Closure Compiler's advanced optimizations.

* Remove unused 'outputCode' variable.

* Rename 'run_X_in_browser.js' to 'webdriver.js'

The Mocha and generator tests can both be run either manually or via our webdriver.  In all cases they run in a browser.  These two 'run_X_in_browser.js' files only apply to webdriver, thus they are confusingly named.

Also delete completely unused (and broken) `run_all_tests.sh`

* Linting improvements to mocha/webdriver.js

Still not at 100%.  Complains about require/module/process/__dirname not being defined in multiple places.

* runTestBlock -> runTestFunction

'Block' means something very different in Blockly.

* Removal of `var` from scripts.

* Add webdriver test to verify compile test worked.

* Resolve conficts with 'develop'.

* Address PR comments.

scripts/gulpfiles/appengine_tasks.js

@@ -8,16 +8,16 @@
  * @fileoverview Gulp script to deploy Blockly demos on appengine.
  */
 
-var gulp = require('gulp');
+const gulp = require('gulp');
 
-var fs = require('fs');
-var rimraf = require('rimraf');
-var path = require('path');
-var execSync = require('child_process').execSync;
+const fs = require('fs');
+const rimraf = require('rimraf');
+const path = require('path');
+const execSync = require('child_process').execSync;
 const buildTasks = require('./build_tasks.js');
 const packageTasks = require('./package_tasks.js');
 
-var packageJson = require('../../package.json');
+const packageJson = require('../../package.json');
 const demoTmpDir = '../_deploy';
 const demoStaticTmpDir = '../_deploy/static';
 
@@ -121,10 +121,10 @@ function deployAndClean(done) {
  * Constructs a beta demo version name based on the current date.
  */
 function getDemosBetaVersion() {
-  var date = new Date();
-  var mm = date.getMonth() + 1; // Month, 0-11
-  var dd = date.getDate(); // Day of the month, 1-31
-  var yyyy = date.getFullYear();
+  const date = new Date();
+  const mm = date.getMonth() + 1;  // Month, 0-11
+  const dd = date.getDate();  // Day of the month, 1-31
+  const yyyy = date.getFullYear();
   return `${yyyy}${mm < 10 ? '0' + mm : mm}${dd}-beta`;
 }
 
@@ -140,7 +140,7 @@ function deployBetaAndClean(done) {
 
 /**
  * Prepares demos.
- * 
+ *
  * Prerequisites (invoked): clean, build
  */
 const prepareDemos = gulp.series(