Support 'dart.library.X' env variables in the VM.

tests/language/language.status

 # Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 # for details. All rights reserved. Use of this source code is governed by a
 # BSD-style license that can be found in the LICENSE file.
 
 # This directory contains tests that are intended to show the
 # current state of the language.
 
 [ ($compiler == none || $compiler == precompiler || $compiler == dart2app) ]
 tearoff_constructor_basic_test: Skip # Crashes in checked mode -- hausner investigating
 
@@ skipping 27 matching lines @@
 # Non-contractive types are not supported in the vm.
 cyclic_type_test/02: Fail, OK
 cyclic_type_test/04: Fail, OK
 cyclic_type2_test: Fail, OK
 least_upper_bound_expansive_test/*: Fail, OK
 
 async_star_regression_2238_test: CompileTimeError, RuntimeError # drt only runtime-errs.
 async_star_cancel_while_paused_test: RuntimeError
 async_star_await_pauses_test: Skip # Times out. Issue 23996
 
-library_env_test: RuntimeError
-
 accessor_conflict_export2_test: RuntimeError # Issue 25625
 accessor_conflict_import2_test: RuntimeError # Issue 25625
 accessor_conflict_import_prefixed2_test: RuntimeError # Issue 25625
 accessor_conflict_import_prefixed_test: RuntimeError # Issue 25625
 
 [ ($compiler == none || $compiler == precompiler || $compiler == dart2app) && ($runtime == vm || $runtime == dart_precompiled || $runtime == dart_product) ]
 
 class_keyword_test/02: MissingCompileTimeError # Issue 13627
 unicode_bom_test: Fail # Issue 16067
 vm/debug_break_enabled_vm_test/01: Crash, OK # Expected to hit breakpoint.
@@ skipping 130 matching lines @@
 deopt_inlined_function_lazy_test: Pass, Crash # Incompatible flag: --deoptimize-alot
 
 [ $runtime == dart_product ]
 # Deferred loading happens eagerly (not sure why this works on precompiled code).
 deferred_static_seperate_test: Skip
 deferred_constraints_type_annotation_test/new_before_load: Skip
 regress_22443_test: Skip
 
 [ $runtime == vm && $mode == product ]
 vm/type_vm_test: Fail,OK  # Expects exact type name.
+
+[ $compiler == none && $browser ]
+# The following tests are supposed to fail.
+library_env_test/has_io_support: RuntimeError, OK
+library_env_test/has_no_html_support: RuntimeError, OK
+library_env_test/has_no_mirror_support: RuntimeError, OK
+
+[ $compiler == none && $browser != true ]
+# The following tests are supposed to fail.
+library_env_test/has_html_support: RuntimeError, OK
+library_env_test/has_no_io_support: RuntimeError, OK
+library_env_test/has_no_mirror_support: RuntimeError, OK