harden tests for heap graph reconstruction

[sam-herman]

Description

• Harden test for the cases where heap graph reconstruction and ravv to graph ordinal mappings are not the identity mapping.
• Fix bug when graph ord mapping is used with the remmaped RAVV
• Move to remmaped interface for buildAndMerge to avoid bugs of remmpaing ords twice
• Add interface for providing the executor pools for the buildAndMerge method -important for downstream dependencies with centralized resource management

[github-actions]

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[marianotepper]

There seems to be a failure from one of the tests that this PR is adding. In testIncrementalInsertionFromOnDiskIndex_withNonIdentityOrdinalMapping

[sam-herman]

There seems to be a failure from one of the tests that this PR is adding. In testIncrementalInsertionFromOnDiskIndex_withNonIdentityOrdinalMapping

Yeah, it is now more robust, the recall calculation need to be more statistically significant so I increased number of vectors + beamsize and number of query vectors participating in average recall calculation.

[marianotepper]

A few comments here and there.

[sam-herman]

One of the tests failed due to a different test not related to this change:

Error: 1,882 [ERROR] io.github.jbellis.jvector.quantization.TestCompressedVectors
Error: 1,882 [ERROR] 	at org.apache.maven.plugin.surefire.booterclient.ForkStarter.fork(ForkStarter.java:643)
Error: 1,882 [ERROR] 	at org.apache.maven.plugin.surefire.booterclient.ForkStarter.lambda$null$3(ForkStarter.java:350)
Error: 1,882 [ERROR] 	at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:317)
Error: 1,882 [ERROR] 	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1144)
Error: 1,882 [ERROR] 	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:642)
Error: 1,882 [ERROR] 	at java.base/java.lang.Thread.run(Thread.java:1570)
Error: 1,882 [ERROR] -> [Help 1]

I am re-running this test so we can have a whole green panel

[marianotepper]

LGTM

[jshook]

LGTM, nice to see added docs