8242214: NullPointerException in JDK 14 javac compiling a method reference

Ensuring a proper receiver is used to invoke protected method when method reference is unrolled into a lambda.

Reviewed-by: vromero

test/langtools/tools/javac/lambda/methodReference/pack/I.java

@@ -29,4 +29,8 @@ public class I {
     protected String readFile(Path file) {
         return file.toString();
     }
+
+    protected static String readFile2(Path file) {
+        return file.toString();
+    }
 }