Java: Add some initial stubs for methods like java.util.stream.Stream.

java/ql/test/utils/model-generator/typebasedflow/p/Stream.java

@@ -0,0 +1,34 @@
+package p;
+
+import java.util.function.*;
+import java.util.Iterator;
+import java.util.stream.Collector;
+
+public class Stream<T> {
+
+    public Iterator<T> iterator() {
+        return null;
+    }
+
+    // public boolean allMatch(Predicate<? super T> predicate) {
+    // throw null;
+    // }
+
+    // public <R> R collect(Supplier<R> supplier, BiConsumer<R, ? super T>
+    // accumulator, BiConsumer<R, R> combiner) {
+    // throw null;
+    // }
+
+    // public <R, A> R collect(Collector<? super T, A, R> collector) {
+    // throw null;
+    // }
+
+    // public static <T> Stream<T> concat(Stream<? extends T> a, Stream<? extends T>
+    // b) {
+    // throw null;
+    // }
+
+    public Stream<T> distinct() {
+        throw null;
+    }
+}