IDL: Add build target for IDL dictionary impl generation in core

Source/core/testing/Internals.idl

Index: Source/core/testing/Internals.idl
diff --git a/Source/core/testing/Internals.idl b/Source/core/testing/Internals.idl
index 2f154eb59704fb176663382391608e5492ddcffc..aa1a02ac4cf528c822a177f34515b456d707c895 100644
--- a/Source/core/testing/Internals.idl
+++ b/Source/core/testing/Internals.idl
@@ -212,10 +212,11 @@
     MallocStatistics mallocStatistics();
     TypeConversions typeConversions();
 
-    // This is enabled only in Debug builds.
+    // These are enabled only in Debug builds.
     // This is because we want to avoid putting the byte stream of testing private scripts
     // into the binary of Release builds.
     PrivateScriptTest privateScriptTest();
+    DictionaryTest dictionaryTest();
 
     DOMString[] getReferencedFilePaths();