message: Fixed python 3 error in run_tests script
diff: @@ -74,7 +74,7 @@ class Host(object):
  ispc_ext = ""
  if self.is_windows():
  ispc_ext = ".exe"
  - if os.environ["ISPC_HOME"]:
  + if "ISPC_HOME" in os.environ:
  if os.path.exists(os.environ["ISPC_HOME"] + os.sep + "ispc" + ispc_ext):
  ispc_exe = os.environ["ISPC_HOME"] + os.sep + "ispc" + ispc_ext
  PATH_dir = os.environ["PATH"].split(os.pathsep)
  