[libc++] Use Lit utilities instead of old libcxx utilities for str/by…

…tes conversions

The libcxx.util utilities don't work properly, and we should remove them
when we get rid of compiler.py. In particular, libcxx.util.to_string
appears to be completely broken.

libcxx/test/libcxx/selftest/dsl/lit.local.cfg

@@ -10,7 +10,8 @@
 # in this directory. We then base64-decode them from the tests when we need to.
 # Another option would be to have a way to prevent expansion in Lit itself.
 import base64
-base64Encode = lambda s: base64.b64encode(s.encode()).decode()
+import lit.util
+base64Encode = lambda s: lit.util.to_string(base64.b64encode(lit.util.to_bytes(s)))
 escaped = [(k.replace('%{', '%{escaped_'), base64Encode(v)) for (k, v) in config.substitutions]
 config.substitutions.extend(escaped)
 

libcxx/utils/libcxx/test/target_info.py

@@ -7,14 +7,15 @@
 #===----------------------------------------------------------------------===//
 
 import importlib
+import lit.util
 import locale
 import os
 import platform
 import re
 import subprocess
 import sys
 
-from libcxx.util import executeCommand, to_string
+from libcxx.util import executeCommand
 
 class DefaultTargetInfo(object):
     def __init__(self, full_config):
@@ -91,12 +92,12 @@ def __init__(self, full_config):
         super(DarwinLocalTI, self).__init__(full_config)
 
     def is_host_macosx(self):
-        name = to_string(subprocess.check_output(['sw_vers', '-productName'])).strip()
+        name = lit.util.to_string(subprocess.check_output(['sw_vers', '-productName'])).strip()
         return name == "Mac OS X"
 
     def get_macosx_version(self):
         assert self.is_host_macosx()
-        version = to_string(subprocess.check_output(['sw_vers', '-productVersion'])).strip()
+        version = lit.util.to_string(subprocess.check_output(['sw_vers', '-productVersion'])).strip()
         version = re.sub(r'([0-9]+\.[0-9]+)(\..*)?', r'\1', version)
         return version