Report all objects with hash mismatches in a single go

The object hash test previously stopped when it hit the first object with
a mismatched hash. This meant that if you changed a couple objects, you
had to run the test, fix the first, run the test, fix the next, etc.
This patch collects all the data and then asserts the delta set, if
there were mismatches.

Change-Id: Ie35a4dbd6941a1f31e0cef7ea56fa2cc5e9a8ef0
Merge "Report all objects with hash mismatches in a single go"