test: set PYTHONIOENCODING for all targets

This encodes the printing stream, and fixes the printing for the message
in `incrParse/simple`.

Author: compnerd

test/lit.cfg

@@ -183,7 +183,7 @@ def append_to_env_path(directory):
     config.environment['PATH'] = \
         os.path.pathsep.join((directory, config.environment['PATH']))
 
-if kIsWindows:
+if sys.version_info[0] >= 3:
     config.environment['PYTHONIOENCODING'] = 'UTF8'
 
 # Tweak the PATH to include the tools dir and the scripts dir.