Make pub's binstubs resilient to changes in snapshot format.

sdk/lib/_internal/pub/test/global/binstubs/binstub_runs_executable_test.dart

Index: sdk/lib/_internal/pub/test/global/binstubs/binstub_runs_executable_test.dart
diff --git a/sdk/lib/_internal/pub/test/global/binstubs/binstub_runs_executable_test.dart b/sdk/lib/_internal/pub/test/global/binstubs/binstub_runs_executable_test.dart
index 30167b0e796234769d7ca6f6c59c3a4092a454dd..a3353e967e6841b0e0718fa33e10e9b282f699f6 100644
--- a/sdk/lib/_internal/pub/test/global/binstubs/binstub_runs_executable_test.dart
+++ b/sdk/lib/_internal/pub/test/global/binstubs/binstub_runs_executable_test.dart
@@ -62,16 +62,3 @@ main() {
     process.shouldExit();
   });
 }
-
-/// The buildbots do not have the Dart SDK (containing "dart" and "pub") on
-/// their PATH, so we need to spawn the binstub process with a PATH that
-/// explicitly includes it.
-getEnvironment() {
-  var binDir = p.dirname(Platform.executable);
-  var separator = Platform.operatingSystem == "windows" ? ";" : ":";
-  var path = "${Platform.environment["PATH"]}$separator$binDir";
-
-  var environment = getPubTestEnvironment();
-  environment["PATH"] = path;
-  return environment;
-}