functional expressions: allow to delete/change signature of default methods of functional interfaces

java/java-tests/testData/refactoring/safeDelete/FunctionalInterfaceDefaultMethod.java

@@ -0,0 +1,12 @@
+interface SAM {
+  default void fo<caret>o(int i){}
+  void bar(int i);
+}
+
+class Test {
+
+  {
+    SAM sam = (i) -> {};
+  }
+
+}

java/java-tests/testData/refactoring/safeDelete/FunctionalInterfaceDefaultMethod_after.java

@@ -0,0 +1,11 @@
+interface SAM {
+    void bar(int i);
+}
+
+class Test {
+
+  {
+    SAM sam = (i) -> {};
+  }
+
+}