dart2js cps: Ensure JSArray is emitted when we see a type cast.

tests/compiler/dart2js_extra/dart2js_extra.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.
 
 [ $compiler == dart2js ]
 16407_test: Fail # Issue 16407
 class_test: Fail
 statements_test: Fail
 typed_locals_test: Fail
 no_such_method_test: Fail # Wrong Invocation.memberName.
@@ skipping 46 matching lines @@
 deferred/*: Skip # Issue 17458
 
 [ $compiler == dart2js && $csp ]
 deferred_fail_and_retry_test: SkipByDesign # Uses eval to simulate failed loading.
 deferred_fail_and_retry_worker_test: SkipByDesign # Uses eval to simulate failed loading.
 
 [ $host_checked && $compiler == dart2js && $cps_ir ]
 21724_test: Crash # Please triage this failure.
 
 [ $compiler == dart2js && $cps_ir ]
-11673_test: RuntimeError # Cannot read property 'prototype' of undefined
-12320_test: RuntimeError # Cannot read property 'prototype' of undefined
 16407_test: Pass # Please triage this failure.
-22487_test: RuntimeError # Cannot read property 'prototype' of undefined
 22868_test: Crash # (main()async{var clo...  cannot handle async/sync*/async* functions
 22895_test: Crash # (main()async{var clo...  cannot handle async/sync*/async* functions
-23404_test: RuntimeError # Cannot read property 'prototype' of undefined
 23432_test : RuntimeError # 
-LayoutTests_fast_mediastream_getusermedia_t01_test/none: RuntimeError # Cannot read property 'prototype' of undefined
 async_stacktrace_test/asyncStar: Crash # (runTests()async{awa...  cannot handle async/sync*/async* functions
 async_stacktrace_test/none: Crash # (runTests()async{awa...  cannot handle async/sync*/async* functions
-closure5_test: RuntimeError # Cannot read property 'prototype' of undefined
 closure_capture5_test: Crash # (i=0): For-loop variable captured in loop header
 conditional_send_test: RuntimeError # receiver.get$_collection$_nums is not a function
 deferred/deferred_class_test: RuntimeError # receiver.get$_collection$_nums is not a function
 deferred/deferred_constant2_test: RuntimeError # receiver.get$_collection$_nums is not a function
 deferred/deferred_constant3_test: RuntimeError # receiver.get$_collection$_nums is not a function
 deferred/deferred_constant4_test: RuntimeError # receiver.get$_collection$_nums is not a function
 deferred/deferred_function_test: RuntimeError # receiver.get$_collection$_nums is not a function
 deferred/deferred_mirrors1_test: RuntimeError # receiver.get$_collection$_nums is not a function
 deferred/deferred_mirrors2_test : RuntimeError # TypeError: receiver.get$_collection$_nums is not a function
 deferred/deferred_overlapping_test: RuntimeError # receiver.get$_collection$_nums is not a function
 if_null_test: RuntimeError # receiver.get$_collection$_nums is not a function
 mirror_invalid_field_access3_test: Crash # Internal Error: No default constructor available.
 mirror_invalid_field_access_test: Crash # Internal Error: No default constructor available.
 mirror_invalid_invoke3_test: Crash # Internal Error: No default constructor available.
 mirror_invalid_invoke_test: Crash # Internal Error: No default constructor available.
 mirror_printer_test: Crash # Internal Error: No default constructor available.
 mirror_test: Crash # Internal Error: No default constructor available.
 mirror_type_inference_field2_test: Crash # Internal Error: No default constructor available.
 mirror_type_inference_field_test: Crash # Internal Error: No default constructor available.
 mirror_type_inference_function_test: Crash # Internal Error: No default constructor available.
 mirrors_used_warning2_test : RuntimeError # TypeError: receiver.get$_nums is not a function
 mirrors_used_warning_test/minif : RuntimeError # TypeError: receiver.get$_nums is not a function
 mirrors_used_warning_test/none : RuntimeError # TypeError: receiver.get$_nums is not a function
 reflect_native_types_test: Crash # Internal Error: No default constructor available.
-runtime_type_test: RuntimeError # Cannot read property 'prototype' of undefined
 switch_test/none: Crash # (switch (val){foo:ba...  continue to a labeled switch case
 timer_test: RuntimeError # receiver.get$_collection$_nums is not a function
 no_such_method_test : Crash # Internal Error: No default constructor available.
 mirrors_used_closure_test : Crash # Internal Error: No default constructor available.