linux-user: Make TARGET_NR_setgroups affect only the current thread

linux-user: Make TARGET_NR_setgroups affect only the current thread

Like TARGET_NR_setuid, TARGET_NR_setgroups should affect only the
calling thread, and not the entire process. Therefore, implement it
using a syscall, and not a libc call.

Cc: qemu-stable@nongnu.org
Fixes: 19b84f3c35d7 ("added setgroups and getgroups syscalls")
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-Id: <20240614154710.1078766-1-iii@linux.ibm.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>