Add package config support to dart:isolate

tests/standalone/standalone.status

Index: tests/standalone/standalone.status
diff --git a/tests/standalone/standalone.status b/tests/standalone/standalone.status
index 948099db9816894d7ac917031ebe6b6931d50f3e..8c13fea2442b55656551ab2e71ea0ccd8b517b67 100644
--- a/tests/standalone/standalone.status
+++ b/tests/standalone/standalone.status
@@ -11,7 +11,9 @@ package/invalid_uri_test: Fail, OK # CompileTimeErrors intentionally
 package/scenarios/packages_file_strange_formatting/empty_package_dir_test: Fail, OK # CompileTimeErrors intentionally
 package/scenarios/empty_packages_file/empty_packages_file_discovery_test: Fail, OK # CompileTimeErrors intentionally
 package/scenarios/empty_packages_file/empty_packages_file_option_test: Fail, OK # CompileTimeErrors intentionally
-package/scenarios/invalid/*: Fail, OK # CompileTimeErrors intentionally
+package/scenarios/invalid/invalid_package_name_test: RuntimeError # RuntimeErrors intentionally
+package/scenarios/invalid/same_package_twice_test.dart: RuntimeError # RuntimeErrors intentionally
+
 
 issue14236_test: Pass # Do not remove this line. It serves as a marker for Issue 14516 comment #4.