Remove outdated entries from .packages

Change-Id: I52caf28cdfa17b0481f24d317ffb384bac13284e
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/96822
Reviewed-by: William Hesse <whesse@google.com>
Commit-Queue: Kevin Moore <kevmoo@google.com>
diff --git a/.packages b/.packages
index a686ef2..b01204c 100644
--- a/.packages
+++ b/.packages
@@ -16,7 +16,6 @@
 args:third_party/pkg/args/lib
 async:third_party/pkg/async/lib
 async_helper:pkg/async_helper/lib
-barback:third_party/pkg/barback/lib
 bazel_worker:third_party/pkg/bazel_worker/lib
 boolean_selector:third_party/pkg/boolean_selector/lib
 build_integration:pkg/build_integration/lib
@@ -48,7 +47,6 @@
 http_retry:third_party/pkg/http_retry/lib
 http_throttle:third_party/pkg/http_throttle/lib
 intl:third_party/pkg/intl/lib
-isolate:third_party/pkg/isolate/lib
 js:pkg/js/lib
 js_ast:pkg/js_ast/lib
 js_runtime:sdk/lib/_internal/js_runtime/lib