dfa: turn on contract inference from source

java/java-tests/testData/inspection/dataFlow/fixture/CatchRuntimeException.java

@@ -36,7 +36,7 @@ class BrokenAlignment {
   }
 
   public void bar(@NotNull Object foo) {
-    assert <warning descr="Condition 'foo != null' is always 'true'">foo != null</warning>;
+    if (<warning descr="Condition 'foo != null' is always 'true'">foo != null</warning>);
   }
 
   public void bar2(@NotNull Object foo) {

java/java-tests/testData/inspection/dataFlow/fixture/UseInferredContracts.java

@@ -0,0 +1,15 @@
+import org.jetbrains.annotations.Nullable;
+
+class Doo {
+
+  boolean isNotNull(@Nullable Object o) {
+    return o != null;
+  }
+
+  void foo(@Nullable String s) {
+    if (isNotNull(s)) {
+      System.out.println(s.length());
+    }
+  }
+
+}