GH-4718 optimize approvedEmpty and deprecatedEmpty

[hmottestad]

GitHub issue resolved: #4718

Briefly describe the changes proposed in this PR:

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PR Author Checklist (see the contributor guidelines for more details):

• my pull request is self-contained
• I've added tests for the changes I made
• I've applied code formatting (you can use mvn process-resources to format from the command line)
• I've squashed my commits where necessary
• every commit message starts with the issue number (GH-xxxx) followed by a meaningful description of the change

[hmottestad]

Before

Benchmark                                               Mode  Cnt      Score      Error  Units
OverflowBenchmarkSynthetic.loadLotsOfDataEmptyStore     avgt   10  11525.521 ± 2709.930  ms/op
OverflowBenchmarkSynthetic.loadLotsOfDataNonEmptyStore  avgt   10  17358.805 ± 5673.566  ms/op

After

Benchmark                                               Mode  Cnt      Score      Error  Units
OverflowBenchmarkSynthetic.loadLotsOfDataEmptyStore     avgt   10  13667.451 ± 6103.327  ms/op
OverflowBenchmarkSynthetic.loadLotsOfDataNonEmptyStore  avgt   10  17120.881 ± 9069.072  ms/op