remove unused imports

Author: erik-krogh

javascript/extractor/src/com/semmle/js/extractor/CFGExtractor.java

@@ -112,9 +112,7 @@
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
-import java.util.function.IntFunction;
 import java.util.HashMap;
-import java.util.HashSet;
 import java.util.Iterator;
 import java.util.LinkedHashMap;
 import java.util.LinkedHashSet;