fix #1954
fix benchmarks
Merge pull request #2095 from jakesjews/3.8.x

fix benchmarks
don't mark path as dirty when using custom getter
Fix #1794: don't take cached populated if array length has changed
Merge pull request #2100 from pgherveou/3.8.x

don't mark path as dirty when using custom getter
Merge pull request #2088 from archangel-irk/3.8.x

fix #1954
Fix #1672 by patching in #2084
Fix #2082
Fix #2114: add allowDiskUse helper to aggregation
Fix 2.4/2.2 tests for new allowDiskUse helper
Release 3.8.12
Now working on 3.8.13