[C++] Change the default number of jobs from 64 to 32
[C++] Change the default number of jobs from 64 to 32

dalinaum/kati,danw/kati,colincross/kati,colincross/kati,google/kati,danw/kati,dalinaum/kati,dalinaum/kati,pombredanne/kati,pombredanne/kati,google/kati,danw/kati,google/kati,colincross/kati,pombredanne/kati,danw/kati,shinh/kati,shinh/kati,google/kati,shinh/kati,pombredanne/kati,shinh/kati,pombredanne/kati,google/kati,dalinaum/kati,shinh/kati,colincross/kati,danw/kati,colincross/kati,dalinaum/kati,danw/kati,pombredanne/kati,colincross/kati,shinh/kati