java: check accessibility of classes: warn on static imports, do not for supers of method signatures types

GitOrigin-RevId: 94d15750d549eca51ad5c0b0767ae5387b7424e7

java/java-tests/testData/codeInsight/multipleJdks/java7/p/StaticCallOnChildWithNotAccessibleParent.java

@@ -1,3 +1,8 @@
 package p;
 
 public class ChildClass extends BaseClass {}
+class ChildClass2 {
+  public static ChildClass childClass() {
+    return null;
+  }
+}