Ingest coverage data only for the files in the filter that actually h…

…ave some. Fixes sebastianbergmann#876

src/Driver/PcovDriver.php

@@ -47,7 +47,7 @@ public function stop(): RawCodeCoverageData
 
         $collect = \pcov\collect(
             \pcov\inclusive,
-            !$this->filter->isEmpty() ? $this->filter->files() : \pcov\waiting()
+            $this->filter->isEmpty() ? \pcov\waiting() : array_intersect(\pcov\waiting(), $this->filter->files())
         );
 
         \pcov\clear();