Fixes three issues:
1. Retrieving the latest evaluation index was not properly selecting the
greatest index. This would undermine checks we had to reduce the number
of evaluations created when the latest eval index was greater than any
alloc change
2. Fix an issue where the blocking query code was using the incorrect
index such that the index was higher than necassary.
3. Special case handling of blocked evaluation since the create/snapshot
index is no particularly useful since they can be reblocked.

Denormalize jobs in AppendAllocs:
AppendAlloc was originally only ever called for inplace upgrades and new
allocations. Both these code paths would remove the job from the
allocation. Now we use this to also add fields such as FollowupEvalID
which did not normalize the job. This is only a performance enhancement.

Ignore terminal allocs:
Failed allocations are annotated with the followup Eval ID when one is
created to replace the failed allocation. However, in the plan applier,
when we check if allocations fit, these terminal allocations were not
filtered. This could result in the plan being rejected if the node would
be overcommited if the terminal allocations resources were considered.

Give blocked evals a unique triggerby reason to make debugging a chain
of evaluations easier.

Fix deployment watcher index usage

Unique TriggerBy for blocked evals

needs unit test

Add a missing eval trigger reason