migrate @JavaDebug to @JavaDerive(toString=true)

This will make it easier to add a new sythetic methods in the future.

Bug: 171271915
Test: aidl_unittests / aidl_integration_test
Change-Id: I043c1320821c1821faede60fa8608ff7cc79bd6c
diff --git a/aidl_language.h b/aidl_language.h
index 1e8b600..73f2d66 100644
--- a/aidl_language.h
+++ b/aidl_language.h
@@ -165,7 +165,7 @@
     NULLABLE,
     UTF8_IN_CPP,
     JAVA_PASSTHROUGH,
-    JAVA_DEBUG,
+    JAVA_DERIVE,
     JAVA_ONLY_IMMUTABLE,
     FIXED_SIZE,
     DESCRIPTOR,
@@ -240,7 +240,7 @@
   bool IsFixedSize() const;
   bool IsStableApiParcelable(Options::Language lang) const;
   bool IsHide() const;
-  bool IsJavaDebug() const;
+  const AidlAnnotation* JavaDerive() const;
   std::string GetDescriptor() const;
 
   void DumpAnnotations(CodeWriter* writer) const;