check_software: tolerate libmvec in ldd check

libmvec ( https://sourceware.org/glibc/wiki/libmvec ) is part of
libc.

$ dpkg -S /lib/x86_64-linux-gnu/libmvec-2.24.so
libc6:amd64: /lib/x86_64-linux-gnu/libmvec-2.24.so

slapos/testing/check_software.py

@@ -70,6 +70,7 @@ def checkSoftware(slap, software_url):
       'libgcc_s',
       'libgomp',
       'libm',
+      'libmvec',
       'libnsl',
       'libpthread',
       'libthread_db',