replace a use in libcxx

Author: kikairoya

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

@@ -10,6 +10,6 @@
 # within the test.
 import base64, lit.util, pickle
 
-base64Encode = lambda s: lit.util.to_string(base64.b64encode(lit.util.to_bytes(s)))
+base64Encode = lambda s: base64.b64encode(s).decode("utf-8")
 escapedSubstitutions = base64Encode(pickle.dumps(config.substitutions))
 config.substitutions.append(("%{substitutions}", escapedSubstitutions))