Add a VerifierDeps::Dump method.

Also, fix the Encode/Decode logic around dex file order:
iterating over a std::map doesn't guarantee insertion order.

test: verifier_deps_test
bug: 30937355

Change-Id: Id3efd703b3c8ca21ab49c2600c612c132fb021cd
diff --git a/compiler/oat_writer.cc b/compiler/oat_writer.cc
index 6cbca7a..f9173f5 100644
--- a/compiler/oat_writer.cc
+++ b/compiler/oat_writer.cc
@@ -1759,7 +1759,7 @@
   }
 
   std::vector<uint8_t> buffer;
-  verifier_deps->Encode(&buffer);
+  verifier_deps->Encode(*dex_files_, &buffer);
 
   if (!vdex_out->WriteFully(buffer.data(), buffer.size())) {
     PLOG(ERROR) << "Failed to write verifier deps."