MDL-72239 phpunit: Assert the number of db queries to be less or equal

The course unit test assumes the number of db call. This assumption
is correct in vanilla moodle only. Once some plugins installed their
observers may do extra db calls. Due to caching the number of actual
db calls in the unit test may be fewer.

course/tests/courselib_test.php

@@ -4676,7 +4676,7 @@ class core_course_courselib_testcase extends advanced_testcase {
         sort($expectedresult);
 
         $this->assertEquals($expectedresult, $actualresult);
-        $this->assertEquals($expecteddbqueries, $DB->perf_get_queries() - $initialquerycount);
+        $this->assertLessThanOrEqual($expecteddbqueries, $DB->perf_get_queries() - $initialquerycount);
     }
 
     /**