MDL-46267 core: Remove $CFG->httpswwwroot

* It's unnecessary since $CFG->loginhttps has already been removed and
  it's no longer being used in core anymore.

lib/phpunit/tests/basic_test.php

@@ -52,9 +52,6 @@ class core_phpunit_basic_testcase extends basic_testcase {
      */
     public function test_bootstrap() {
         global $CFG;
-        // The use of httpswwwroot is deprecated, but we are still setting it for backwards compatibility.
-        $this->assertTrue(isset($CFG->httpswwwroot));
-        $this->assertEquals($CFG->httpswwwroot, $CFG->wwwroot);
         $this->assertEquals($CFG->prefix, $CFG->phpunit_prefix);
     }