Remove deleted language test from VM stress test list.

Change-Id: I45b5c58cc040fa0624de4c3643ccafe2d4b26071
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/409183
Commit-Queue: Alexander Markov <[email protected]>
Auto-Submit: Bob Nystrom <[email protected]>
Reviewed-by: Alexander Markov <[email protected]>

Author: munificent

runtime/tests/concurrency/stress_test_list.json

@@ -1115,7 +1115,6 @@
   "../../../tests/language/deferred/load_inval_code_test.dart",
   "../../../tests/language/deferred/loading_unit_root_has_only_export_test.dart",
   "../../../tests/language/deferred/mixin_test.dart",
-  "../../../tests/language/deferred/no_prefix_runtime_test.dart",
   "../../../tests/language/deferred/no_such_method_test.dart",
   "../../../tests/language/deferred/only_constant_test.dart",
   "../../../tests/language/deferred/optimized_test.dart",