Change our 'is int' check to use Math.floor instead of a smi check.

tests/html/html.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.
 
 event_test: Skip  # Issue 1996
 webgl_1_test: Skip  # Issue 1495
 xmldocument_test: Skip  # XML in dart:html is incomplete
 xmlelement_test: Skip  # XML in dart:html is incomplete
 measurement_test: Pass, Fail  # Issue 1940
 
@@ skipping 179 matching lines @@
 documentfragment_test: Skip # Timeout
 
 [ $compiler == dart2js && $runtime == chrome && $system == windows]
 css_test: Pass, Fail # Issue #2823
 
 [ $compiler == dart2js && $runtime == ff && $system == windows]
 js_interop_2_test: Fail # Issue 4658.
 
 [ $compiler == dart2js && $checked && $browser]
 fileapi_test: Fail # TypeError: Object #<DirectoryEntry> has no method 'get$name'
-
- # Issue 3720
-async_window_test: Fail
-audiocontext_test: Fail
-audioelement_test: Fail
-b_element_test: Fail
-blob_constructor_test: Fail
-cache_test: Fail
-callbacks_test: Fail
-canvas_pixel_array_type_alias_test: Fail
-canvas_test: Fail
-canvas_using_html_test: Fail
-cross_frame_test: Fail
-css_test: Fail
-cssstyledeclaration_test: Fail
-dart_object_local_storage_test: Fail
-datalistelement_test: Fail
-document_test: Fail
-documentfragment_test: Fail
-dom_constructors_test: Fail
-dom_isolates_test: Fail
-domparser_test: Fail
-element_add_test: Fail
-element_classes_test: Fail
-element_constructor_1_test: Fail
-element_test: Fail
-event_customevent_test: Fail
-events_test: Fail
-exceptions_test: Fail
-form_data_test: Fail
-form_element_test: Fail
-hidden_dom_1_test: Fail
-hidden_dom_2_test: Fail
-history_test: Fail
-htmlaudioelement_test: Fail
-htmlcollection_test: Fail
-htmlelement_test: Fail
-indexeddb_1_test: Fail
-indexeddb_2_test: Fail
-indexeddb_3_test: Fail
-indexeddb_4_test: Fail
-inner_frame_test: Fail
-instance_of_test: Fail
-js_interop_1_test: Fail
-js_interop_2_test: Fail
-js_interop_3_test: Fail
-js_interop_4_test: Fail
-js_interop_element_test: Fail
-js_interop_func_passing_test: Fail
-js_interop_obj_invoke_test: Fail
-js_interop_obj_passing_test: Fail
-key_name_location_test: Fail
-localstorage_test: Fail
-location_test: Fail
-messageevent_test: Fail
-mutationobserver_test: Fail
-native_gc_test: Fail
-node_test: Fail
-performance_api_test: Fail
-pkg/unittest/test/unittest_test: Fail
-query_test: Fail
-queryall_test: Fail
-serialized_script_value_test: Fail
-shadow_dom_test: Fail
-storage_test: Fail
-svg_1_test: Fail
-svg_2_test: Fail
-svg_3_test: Fail
-svgelement2_test: Fail
-svgelement_test: Fail
-typed_arrays_2_test: Fail
-typed_arrays_3_test: Fail
-typed_arrays_4_test: Fail
-typed_arrays_5_test: Fail
-typed_arrays_arraybuffer_test: Fail
-typed_arrays_dataview_test: Fail
-typed_arrays_range_checks_test: Fail
-typing_test: Fail
-url_test: Fail
-websocket_test: Fail
-websql_test: Fail
-window_eq_test: Fail
-window_mangling_test: Fail
-window_nosuchmethod_test: Fail
-window_open_test: Fail
-xhr_test: Fail
-xsltprocessor_test: Fail
+cross_frame_test: Fail # Caught NoSuchMethodException : method not found: 'is$_WindowImpl'
+window_open_test: Fail # Caught NoSuchMethodException : method not found: 'is$_WindowImpl'