N°4624 Restore processIsolation on tests which actually need it

Warning, one symptom was having the CI returning an empty phpunit.results.xml !!

test/core/dictTest.php

@@ -31,6 +31,11 @@ use Dict;
 use Exception;
 
 
+/**
+ * @runTestsInSeparateProcesses
+ * @preserveGlobalState disabled
+ * @backupGlobals disabled
+ */
 class dictTest extends ItopTestCase
 {
 	private $sEnvName;