Ignore types with methods which have annotations

The motivation is test classes in JUnit 4 and 5 are currently FPs for this. They have methods with `@Test`, so this should fix the FPs.

Author: owen-mc

java/ql/src/Violations of Best Practice/Dead Code/DeadRefTypes.ql

@@ -49,6 +49,7 @@ predicate dead(RefType dead) {
   not dead instanceof AnonymousClass and
   // Exclude classes that look like they may be reflectively constructed.
   not dead.getAnAnnotation() instanceof ReflectiveAccessAnnotation and
+  not dead.getAMethod().getAnAnnotation() instanceof ReflectiveAccessAnnotation and
   // Insist all source ancestors are dead as well.
   forall(RefType t | t.fromSource() and t = getASuperTypePlus(dead) | dead(t)) and
   // Exclude compiler generated classes (e.g. declaring type of adapter functions in Kotlin)

java/ql/test/query-tests/DeadCode/DeadRefTypes/DeadRefTypes.expected

@@ -1,2 +1 @@
-| ClassWithAnnotatedMethod.java:1:7:1:30 | ClassWithAnnotatedMethod | Unused class: ClassWithAnnotatedMethod is not referenced within this codebase. If not used as an external API it should be removed. |
 | UnusedClass.java:1:7:1:17 | UnusedClass | Unused class: UnusedClass is not referenced within this codebase. If not used as an external API it should be removed. |