MDL-49840 testing: Ensure that composer dependencies are updated

We should ensure that composer dependencies are present before running
phpunit and behat. We should also ensure that they match the versions in
the composer.lock file.

Doing so ensures that we have a consistency across the board amongst
testers. All testers are a specific commit will be using the same version
of composer.lock and the same version of the relevant tools.

admin/tool/phpunit/cli/init.php

@@ -39,6 +39,7 @@ require_once(__DIR__.'/../../../../lib/phpunit/bootstraplib.php');
 require_once(__DIR__.'/../../../../lib/testing/lib.php');
 
 echo "Initialising Moodle PHPUnit test environment...\n";
+testing_update_composer_dependencies();
 
 $output = null;
 exec('php --version', $output, $code);
@@ -72,4 +73,6 @@ if ($code == 0) {
 
 passthru("php util.php --buildconfig", $code);
 
+echo "\n";
+echo "PHPUnit test environment setup complete.\n";
 exit(0);