Match old BuildEvalDelta behaviour - no delete missing keys

[jannotti]

Deleting keys that don't exist should not go into EvalDelta

[codecov-commenter]

Codecov Report

Merging #3594 (867c358) into feature/contract-to-contract (abe3c6a) will increase coverage by 0.00%.
The diff coverage is 53.84%.

@@                      Coverage Diff                      @@
##           feature/contract-to-contract    #3594   +/-   ##
=============================================================
  Coverage                         47.88%   47.89%           
=============================================================
  Files                               370      370           
  Lines                             60006    60016   +10     
=============================================================
+ Hits                              28736    28742    +6     
  Misses                            27968    27968           
- Partials                           3302     3306    +4     

Impacted Files	Coverage Δ
data/transactions/logic/eval.go	85.51% <53.84%> (-0.19%)	⬇️
ledger/blockqueue.go	82.18% <0.00%> (-2.88%)	⬇️
catchup/peerSelector.go	98.95% <0.00%> (-1.05%)	⬇️
data/abi/abi_type.go	87.67% <0.00%> (-0.95%)	⬇️
network/wsNetwork.go	62.79% <0.00%> (-0.20%)	⬇️
network/wsPeer.go	68.61% <0.00%> (+0.27%)	⬆️
network/requestTracker.go	71.12% <0.00%> (+0.86%)	⬆️
catchup/service.go	69.62% <0.00%> (+0.98%)	⬆️
cmd/tealdbg/debugger.go	73.86% <0.00%> (+1.00%)	⬆️
util/metrics/counter.go	80.95% <0.00%> (+2.38%)	⬆️
... and 1 more

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