[LyX/master] Fix output of tex2lyx messages in runtests.py

[Juergen Spitzmueller]

commit 38c118b02db38b9864f5b5d01aad2bd0cc931437
Author: Juergen Spitzmueller <spitz at lyx.org>
Date:   Thu Dec 29 15:10:05 2022 +0100

    Fix output of tex2lyx messages in runtests.py
---
 src/tex2lyx/test/runtests.py |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/tex2lyx/test/runtests.py b/src/tex2lyx/test/runtests.py
index 103c74e..aae80c1 100755
--- a/src/tex2lyx/test/runtests.py
+++ b/src/tex2lyx/test/runtests.py
@@ -108,8 +108,8 @@ def main(argv):
         proc.wait()
         err = proc.returncode
         errorstring = proc.stderr.read()
-        if not errorstring is None:
-            print(errorstring)
+        if errorstring:
+            print(errorstring.decode(sys.getfilesystemencoding()))
         if err != 0:
             errors.append(f)
         elif not overwrite: