JDK 14 RFR of JDK-8231443: Add java.io.Serial to list of platform annotations for annotation processing

[Joe Darcy]

Hello,

To avoid spurious warnings about unclaimed annotations, the annotation 
processing machinery in javac maintains a list of platform annotation to 
screen out.  With the new platform annotation java.io.Serial 
(JDK-8202385), being added in JDK 14, the list needs to be updated:

     JDK-8231443 : Add java.io.Serial to list of platform annotations 
for annotation processing
     http://cr.openjdk.java.net/~darcy/8231443.0/

Patch below. It isn't harmful for the annotations list for pre-14 
release to contain an extra entry.

Thanks,

-Joe

--- 
old/src/jdk.compiler/share/classes/com/sun/tools/javac/processing/JavacProcessingEnvironment.java 
2019-09-25 13:08:17.596467999 -0700
+++ 
new/src/jdk.compiler/share/classes/com/sun/tools/javac/processing/JavacProcessingEnvironment.java 
2019-09-25 13:08:17.424553999 -0700
@@ -264,7 +264,9 @@
                        module_prefix + "java.lang.annotation.Native",
                        module_prefix + "java.lang.annotation.Repeatable",
                        module_prefix + "java.lang.annotation.Retention",
-                      module_prefix + "java.lang.annotation.Target");
+                      module_prefix + "java.lang.annotation.Target",
+
+                      module_prefix + "java.io.Serial");
      }

      private void initProcessorLoader() {