[flutter_runner] Use sky_engine from the topaz tree (#43684)

This is to account for the flutter_runner migration.
fxb/fl-250 has more context. This change specifically uses
the build rules that were added as a part of: fxr/333681

packages/flutter/BUILD.gn

@@ -13,15 +13,15 @@ dart_library("flutter") {
   disable_analysis = true
 
   deps = [
-    "//third_party/dart/third_party/pkg/intl",
     "//third_party/dart-pkg/pub/async",
     "//third_party/dart-pkg/pub/collection",
     "//third_party/dart-pkg/pub/meta",
     "//third_party/dart-pkg/pub/typed_data",
     "//third_party/dart-pkg/pub/vector_math",
+    "//third_party/dart/third_party/pkg/intl",
   ]
 
   if (is_fuchsia) {
-    deps += [ "$flutter_root/sky/packages/sky_engine:sky_engine_dart" ]
+    deps += [ "//topaz/runtime/sky_engine:sky_engine_dart" ]
   }
 }

packages/flutter_driver/BUILD.gn

@@ -20,11 +20,11 @@ dart_library("flutter_driver") {
     "//third_party/dart-pkg/pub/json_rpc_2",
     "//third_party/dart-pkg/pub/meta",
     "//third_party/dart-pkg/pub/path",
-    "//third_party/dart-pkg/pub/web_socket_channel",
     "//third_party/dart-pkg/pub/vm_service_client",
+    "//third_party/dart-pkg/pub/web_socket_channel",
   ]
 
   if (is_fuchsia) {
-    deps += [ "$flutter_root/sky/packages/sky_engine:sky_engine_dart" ]
+    deps += [ "//topaz/runtime/sky_engine:sky_engine_dart" ]
   }
 }