Implement mint unboxing on MIPS.

tests/standalone/standalone.status

 # Copyright (c) 2013, 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.
 
 # WARNING:
 # Tests using the multitest feature where failure is expected should *also* be
 # listed in tests/lib/analyzer/analyze_tests.status without the "standalone"
 # prefix.
 
 package/invalid_uri_test: Fail, OK # CompileTimeErrors intentionally
@@ skipping 98 matching lines @@
 
 [ $arch == simarm ]
 out_of_memory_test: Skip # passes on Mac, crashes on Linux
 oom_error_stacktrace_test: Skip # Fails on Linux
 
 [ $arch == simmips || $arch == mips ]
 io/web_socket_test: Pass, Slow
 io/http_server_response_test: Pass, Slow
 out_of_memory_test: Skip # passes on Mac, crashes on Linux
 oom_error_stacktrace_test: Skip # Fails on Linux
+javascript_int_overflow_test: Skip # --throw_on_javascript_int_overflow not supported on MIPS.
 
 [ $arch == mips ]
 io/signals_test: Fail # dartbug.com/17440
 io/file_stat_test: Fail # dartbug.com/17440
 io/process_sync_test: Skip # Starts 10 dart subprocesses, uses too much memory.
 io/signals_test: Skip # Starts 10 dart subprocesses, uses too much memory
 io/file_read_special_device_test: Fail # dartbug.com/17440
 
 [ $arch == mips && $mode == debug ]
 io/web_socket_test: Skip # Times out. Issue 20352
@@ skipping 26 matching lines @@
 package/package_test: CompileTimeError
 
 [ $system == windows ]
 io/skipping_dart2js_compilations_test: Fail # Issue 19551.
 
 [ $system != linux ]
 io/server_socket_reference_issue21383_and_issue21384_test: Skip # Not supported on other platforms so far
 
 [ $arch != ia32 && $arch != x64 && $mode == debug ]
 verified_mem_test: Skip  # Not yet implemented.