[sdk] add gen_snapshot binaries to metadata

Bug: DX-1151
Change-Id: I0e26e17bb28ebb49fa7f9e5ee0943b089bc65c88
diff --git a/runtime/dart/BUILD.gn b/runtime/dart/BUILD.gn
index eb53739..f3beb55 100644
--- a/runtime/dart/BUILD.gn
+++ b/runtime/dart/BUILD.gn
@@ -55,6 +55,8 @@
         "tools/dart_prebuilts/flutter_runner/platform_strong.dill",
         "tools/dart_prebuilts/kernel_compiler.snapshot",
         "tools/dart_prebuilts/frontend_server_tool.snapshot",
+        "tools/dart_prebuilts/gen_snapshot.${current_cpu}",
+        "tools/dart_prebuilts/gen_snapshot_product.${current_cpu}",
       ]
     }
   }