tests: add test demonstarting issue5833 is fixed
Previous patch which fixed issue5832 also fixed issue5833 as the root cause for
both was same. This patch adds test of issue5833 as well.
CHANEGLOG entry is also added for the fixed issues.
utility: convert node from MultipleSuccessorsError to rev numbers (issue5832)
utility.builddependencies() deals with rev numbers but MultipleSuccessorsError
returns nodeid which breaks the function and also breaks instability resolution.
Previou patch demonstrate the breakage. This patch makes sure we convert those
nodeids to rev numbers before processing ahead.