StreamToLoopInspection: support some simple StreamEx scenarios; support Java 9 takeWhile/dropWhile

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/streamToLoop/afterTakeDrop.java

@@ -0,0 +1,45 @@
+// "Replace Stream API chain with loop" "true"
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import java.util.function.Function;
+import java.util.function.Predicate;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+public class Test {
+  // Mock Java 9 methods with inheritor
+  interface MyStream<T> extends Stream<T> {
+    <R> MyStream<R> flatMap(Function<? super T, ? extends Stream<? extends R>> mapper);
+
+    MyStream<T> takeWhile(Predicate<? super T> predicate);
+
+    MyStream<T> dropWhile(Predicate<? super T> predicate);
+
+    static <T> MyStream<T> of(List<T> list) {
+      return null;
+    }
+  }
+
+  public static void test(List<String> data) {
+      List<String> xyz = new ArrayList<>();
+      boolean dropping = true;
+      OUTER:
+      for (String s : data) {
+          for (String s1 : Arrays.asList(s, s + s)) {
+              if (s1.isEmpty()) {
+                  break OUTER;
+              }
+              if (dropping) {
+                  if (s1.length() < 3) {
+                      continue;
+                  }
+                  dropping = false;
+              }
+              xyz.add(s1);
+          }
+      }
+      System.out.println(xyz);
+  }
+}