[functional expressions search] check method equality when applicable (IDEA-276298)

otherwise unrelated lambdas/method references may land in results when intermediate inheritors contain default methods

GitOrigin-RevId: aa5baae37ff676ca477ca41d82b782c42d5fda6c

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/lambda/findUsages/DefaultInHierarchy.java

@@ -0,0 +1,14 @@
+class Clazz {
+    public static void main(String[] args) {
+        Child child = x -> System.out.println();
+    }
+}
+
+interface I {
+    void execute(int i);
+}
+
+interface Child extends I {
+    default void execute(int i) {}
+    void f(int i);
+}