Fix perfresourcecounter test

If qrand() generates a 0, the obtain() is ignored as that is the invalid
ID.

Change-Id: I608f2687a6ca9a40d905c665a3585bffc1ea5695
Reviewed-by: Christian Stenger <christian.stenger@qt.io>

src/plugins/perfprofiler/tests/perfresourcecounter_test.cpp

@@ -140,8 +140,9 @@ void PerfResourceCounterTest::testUnitSized()
     QList<int> ids;
     for (int i = 0; i < 10000; ++i) {
         counter.request(1);
-        int id = qrand();
+        const int id = qrand();
         counter.obtain(id);
+        if (id != 0) // Otherwise it's the invalid ID and that means the allocation "failed".
             ids.append(id);
         QCOMPARE(counter.currentTotal(), ids.length());
     }