StreamToLoop: support condition inside flatMap

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

@@ -0,0 +1,16 @@
+// "Replace Stream API chain with loop" "true"
+
+import java.util.*;
+import java.util.stream.*;
+
+public class Main {
+  public void test(List<List<String>> list) {
+      for (List<String> lst : list) {
+          if (lst != null) {
+              for (String s : lst) {
+                  System.out.println(s);
+              }
+          }
+      }
+  }
+}

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

@@ -0,0 +1,10 @@
+// "Replace Stream API chain with loop" "true"
+
+import java.util.*;
+import java.util.stream.*;
+
+public class Main {
+  public void test(List<List<String>> list) {
+    list.stream().flatMap(lst -> lst == null ? Stream.empty() : lst.stream()).<caret>forEach(System.out::println);
+  }
+}