MDL-81236 javascript: Remove MathJax workaround from MDL-60458

The original workaround was put in place to address the mathjax.sre.js bug that was causing JS errors
as explained in https://github.com/mathjax/MathJax/issues/1854). However, since MathJax 2.7.3,
the underlying problem has been fixed, making the workaround unnecessary.

Additionally, the workaround was causing conflicts with some jQuery plugins.
Removing the workaround has resolved the problem of jQuery plugins failing to load properly.

lib/requirejs/moodle-config.js

@@ -16,8 +16,6 @@ var require = {
       // '*' means all modules will get 'jqueryprivate'
       // for their 'jquery' dependency.
       '*': { jquery: 'jqueryprivate' },
-      // Stub module for 'process'. This is a workaround for a bug in MathJax (see MDL-60458).
-      '*': { process: 'core/first' },
 
       // 'jquery-private' wants the real jQuery module
       // though. If this line was not here, there would

lib/requirejs/readme_moodle.txt

@@ -1,5 +1,4 @@
 Description of import into Moodle:
 // Download from https://requirejs.org/docs/download.html
 // Put the require.js and require.min.js and LICENSE file in this folder.
-// Check if MDL-60458 workaround can be removed.
 // Check that core_privacy\local\request\moodle_content_writer::write_html_data() does not need to be updated.