Add checked-in binary for mips architecture to tools/testing.

tools/utils.py

Index: tools/utils.py
diff --git a/tools/utils.py b/tools/utils.py
index a8ad21d307fbff86d5acc8971f3ade9c49d612f2..81c07fbb9a1a93cd9f1d9985fab7b9a79a23cb01 100644
--- a/tools/utils.py
+++ b/tools/utils.py
@@ -50,6 +50,8 @@ def GuessArchitecture():
   id = platform.machine()
   if id.startswith('arm'):
     return 'arm'
+  elif id.startswith('mips'):
+    return 'mips'
   elif (not id) or (not re.match('(x|i[3-6])86', id) is None):
     return 'ia32'
   elif id == 'i86pc':
@@ -503,6 +505,8 @@ def DartBinary():
     system = GuessOS()
     if arch == 'arm':
       return os.path.join(dart_binary_prefix, system, 'dart-arm')
+    elif arch == 'mips':
+      return os.path.join(dart_binary_prefix, system, 'dart-mips')
     else:
       return os.path.join(dart_binary_prefix, system, 'dart')