Add xAODDigest output to tests

This adds additional log files with the output of diffs of xAODDigest. This is important for helping to diagnose the causes of diffs from diff-root.

Reconstruction/RecExample/RecExRecoTest/test/collateDigest.sh

+#!/bin/bash
+diff $1 $2 | tee temp.log
+grep nTopo $1 | sed 's/^/   /g' >& grep.log
+cat grep.log temp.log >& $3