Update binary compatibility test instructions
Update binary compatibility test instructions

Since autogenerated files are now committed, we no longer need to
rerun ./autogen.sh and actually shouldn't because it could mask
errors.

qpdf/qpdf,qpdf/qpdf,jberkenbilt/qpdf,jberkenbilt/qpdf,jberkenbilt/qpdf,qpdf/qpdf,jberkenbilt/qpdf,qpdf/qpdf,qpdf/qpdf,jberkenbilt/qpdf