Do not assume node is out of bounds in deserializer

[trengrj]

What's being changed:

The HNSW deserializer assumed if id > len(res.Nodes) then the node was out of bounds. However len(res.Nodes) is just set initially to the initialSize of the HNSW index. With the reduction of initialSize in #3005 this triggered Test_NoRace_ManySmallCommitlogs to become flaky with too many links. This PR changes the deserializer to run growIndexToAccomodateNode in these conditions.

Review checklist

• Documentation has been updated, if necessary. Link to changed documentation:
• Chaos pipeline run or not necessary. Link to pipeline:
• All new code is covered by tests where it is reasonable.
• Performance tests have been run or not necessary.

[trengrj]

Note the best way to trigger the flaky test Test_NoRace_ManySmallCommitlogs is to set n := 100000. I have left at 10000 for performance reasons but we may want a chaos pipeline where we check links after many inserts and deletes.

[trengrj]

Updated to target stable/v1.19