Remove duplicate libcore/util/NonNull|Nullable.java files

Test: m checkbuild
Change-Id: I7e5b200906512b11f2f5a0bcbe1ee8704a511bac
diff --git a/non_openjdk_java_files.bp b/non_openjdk_java_files.bp
index c177256..f889637 100644
--- a/non_openjdk_java_files.bp
+++ b/non_openjdk_java_files.bp
@@ -405,8 +405,6 @@
         "luni/src/main/java/libcore/reflect/WildcardTypeImpl.java",
         "luni/src/main/java/libcore/util/CharsetUtils.java",
         "luni/src/main/java/libcore/util/CollectionUtils.java",
-        "luni/src/main/java/libcore/util/NonNull.java",
-        "luni/src/main/java/libcore/util/Nullable.java",
         "luni/src/main/java/libcore/util/NullFromTypeParam.java",
         "luni/src/main/java/libcore/util/Objects.java",
         "luni/src/main/java/org/apache/harmony/xml/ExpatAttributes.java",