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

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

@@ -0,0 +1,10 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<problems>
+  <problem>
+    <file>A.java</file>
+    <line>3</line>
+    <problem_class>unused declaration</problem_class>
+    <description>Method is never used.</description>
+  </problem>
+</problems>
+

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

@@ -0,0 +1,7 @@
+public class A {
+  private A(){}
+  public static A getInstance(){
+    return new A();
+  }
+}
+