do not flag dead code if custom JUnit runner is used (IDEA-25444)

java/java-tests/testData/inspection/deadCode/reachableFromMain/expected.xml

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<problems>  
+</problems>
+

java/java-tests/testData/inspection/deadCode/reachableFromMain/src/A.java

@@ -0,0 +1,10 @@
+public class A {
+    public static void main(String[] args) {
+        B.b();
+    }
+    private static class B{
+        public static B b(){
+            return new B();
+        }
+    }
+}