JS: Accept "regressions" in UnneededDefensiveCode

One of the expectations I removed as we definitely don't want to flag that.

Author: asgerf

javascript/ql/test/query-tests/Expressions/UnneededDefensiveProgramming/global-module-definition.js

@@ -7,5 +7,5 @@ var Mod1;
     var Mod2;
     (function (Mod2) {
         Mod2.p = 42;
-    })(Mod2 || (Mod2 = {})); // $ Alert
+    })(Mod2 || (Mod2 = {}));
 });

javascript/ql/test/query-tests/Expressions/UnneededDefensiveProgramming/tst.js

@@ -10,9 +10,9 @@
     var o_ = o;
     var x_ = x;
 
-    u_ = u_ || e; // $ Alert
-    n_ = n_ || e; // $ Alert
-    o_ = o_ || e; // $ Alert
+    u_ = u_ || e; // $ MISSING: Alert[js/unneeded-defensive-code]
+    n_ = n_ || e; // $ MISSING: Alert[js/unneeded-defensive-code]
+    o_ = o_ || e; // $ MISSING: Alert[js/unneeded-defensive-code]
     x_ = x_ || e;
 
     u && u.p; // $ Alert[js/unneeded-defensive-code]