[vm] Enable mirrors in product mode. Allows building a product mode SDK.

tests/co19/co19-runtime.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.
 
 [ $runtime == vm ]
 # These tests are timing dependent and should be non-flaky once the fix for
 # https://github.com/dart-lang/co19/issues/86 is merged into master.
 # (They are skipped on $runtime == pre_compiled below.)
 LibTest/isolate/Isolate/spawnUri_A01_t06: Pass, Fail # Issue 28269
 LibTest/isolate/Isolate/spawnUri_A01_t07: Pass, Fail  # Issue 28269
@@ skipping 138 matching lines @@
 Language/Statements/Yield_and_Yield_Each/Yield_Each/location_t03: MissingCompileTimeError # Issue 25495
 Language/Statements/Yield_and_Yield_Each/Yield_Each/location_t05: MissingCompileTimeError # Issue 25495
 
 Language/Libraries_and_Scripts/Exports/invalid_uri_t02: Fail
 Language/Libraries_and_Scripts/Exports/reexport_t01: fail # Dart issue 12916
 Language/Libraries_and_Scripts/Imports/invalid_uri_t02: Fail
 Language/Libraries_and_Scripts/Parts/syntax_t06: Fail
 Language/Statements/Labels/syntax_t03: fail # Dart issue 2238
 Language/Statements/Switch/syntax_t02: fail # Dart issue 12908
 
-[ $runtime == dart_precompiled || $mode == product ]
+[ $runtime == dart_precompiled ]
 Language/Metadata/*: SkipByDesign # Uses dart:mirrors
 Language/Expressions/Null/instance_of_class_null_t01: Skip # Uses dart:mirrors
 
 [ $compiler == precompiler || $compiler == app_jit || $mode == product || $runtime == flutter]
 Language/Libraries_and_Scripts/Imports/deferred_import_t01: Skip # Eager loading
 Language/Libraries_and_Scripts/Imports/deferred_import_t02: Skip # Eager loading
 Language/Libraries_and_Scripts/Imports/invalid_uri_deferred_t01: Skip # Eager loading
 Language/Libraries_and_Scripts/Imports/invalid_uri_deferred_t02: Skip # Eager loading
 
 [ $runtime == dart_precompiled ]
@@ skipping 213 matching lines @@
 Language/Types/Static_Types/malformed_type_t02: CompileTimeError
 Language/Types/Static_Types/malformed_type_t03: CompileTimeError
 Language/Types/Static_Types/malformed_type_t04: CompileTimeError
 Language/Types/Static_Types/malformed_type_t05: CompileTimeError
 Language/Types/Static_Types/malformed_type_t06: CompileTimeError
 Language/Expressions/Await_Expressions/syntax_t07: CompileTimeError
 Language/Expressions/Await_Expressions/syntax_t08: CompileTimeError
 Language/Expressions/Await_Expressions/syntax_t09: CompileTimeError
 Language/Expressions/Identifier_Reference/async_and_generator_t01: CompileTimeError