Removes superfluous Dart_ExitScope() call in CreateVmServiceIsolate.

Bug: Crash in Dart in CreateVmServiceIsolate() when bin::VmService::Setup() fails.
Change-Id: I9c640daa49fc9894d00523e0d986154cc4d4e062
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/96802
Auto-Submit: Clement Skau <cskau@google.com>
Reviewed-by: Vyacheslav Egorov <vegorov@google.com>
Reviewed-by: Clement Skau <cskau@google.com>
Commit-Queue: Vyacheslav Egorov <vegorov@google.com>
diff --git a/runtime/bin/dart_embedder_api_impl.cc b/runtime/bin/dart_embedder_api_impl.cc
index ba47d33..4700774 100644
--- a/runtime/bin/dart_embedder_api_impl.cc
+++ b/runtime/bin/dart_embedder_api_impl.cc
@@ -90,8 +90,6 @@
   if (!bin::VmService::Setup(config.ip, config.port, config.dev_mode,
                              /*trace_loading=*/false, config.deterministic)) {
     *error = strdup(bin::VmService::GetErrorMessage());
-    Dart_ExitScope();
-    Dart_ShutdownIsolate();
     return nullptr;
   }