OptionalRefactoringUtil: do not suggest opt.map().stream() -> opt.stream().flatMap() if operation may have side-effect

Side-effect is allowed for Optional.map, but not allowed for Stream.flatMap, and actually may cause a semantics change
Fixes IDEA-207178 Incorrect simplification of optional suggested by inspection

java/java-tests/testData/inspection/optionalChains/afterStreamJava9.java

@@ -15,7 +15,19 @@ public final class MyClass {
     p.name().stream().mapToInt(String::length).forEach(System.out::println);
     p.name().stream().flatMapToInt(String::chars).forEach(System.out::println);
     p.name().filter(n -> !n.isEmpty()).stream().forEach(System.out::println);
+    
+    p.name().stream().flatMap(MyClass::createStream);
+    p.name().map(m -> createStreamSideEffect(m)).orElse(Stream.empty());
 
     Stream<Integer> stream = opt.stream();
   }
+  
+  static Stream<String> createStream(String s) {
+    return Stream.of(s, s);
+  }
+  
+  static Stream<String> createStreamSideEffect(String s) {
+    System.out.println(s);
+    return Stream.of(s, s);
+  }
 }

java/java-tests/testData/inspection/optionalChains/beforeStreamJava9.java

@@ -15,7 +15,19 @@ public final class MyClass {
     p.name().map(n -> IntStream.of(n.length())).orElseGet(IntStream::empty).forEach(System.out::println);
     p.name().map(String::chars).orElseGet(IntStream::empty).forEach(System.out::println);
     p.name().map(n -> n.isEmpty() ? Stream.empty() : Stream.of(n)).orElseGet(Stream::empty).forEach(System.out::println);
+    
+    p.name().map(m -> createStream(m)).orElse(Stream.empty());
+    p.name().map(m -> createStreamSideEffect(m)).orElse(Stream.empty());
 
     Stream<Integer> stream = opt.map(Stream::of).orElseGet(Stream::empty);
   }
+  
+  static Stream<String> createStream(String s) {
+    return Stream.of(s, s);
+  }
+  
+  static Stream<String> createStreamSideEffect(String s) {
+    System.out.println(s);
+    return Stream.of(s, s);
+  }
 }