Fix two bugs in gdbserver thread name handling
Simon pointed out that my earlier patch to gdbserver's thread name
code:
commit
07b3255c3bae7126a0d679f957788560351eb236
Author: Tom Tromey <tom@tromey.com>
Date: Thu Jul 13 17:28:48 2023 -0600
Filter invalid encodings from Linux thread names
... introduced a regression. This bug was that the iconv output was
not \0-terminated.
Looking at it, I found another bug as well -- replace_non_ascii would
not \0-terminate, and also would return the wrong pointer
This patch fixes both of them.
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=31153