Fixed failing tests for /stream.

[dlg99]

Descriptions of the changes in this PR:

Fixed tests for /stream, RocksDB initialization.

Motivation

Tests were failing with " “java.lang.UnsatisfiedLinkError: 'long org.rocksdb.LRUCache.newLRUCache(long, int, boolean, double)'”".

Changes

Fixed following suggestion form facebook/rocksdb#6789
Added
static { RocksDB.loadLibrary(); }
to extract the native library from the jar file etc.

Master Issue: #2550

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[eolivelli]

Looks good.
Can you please create the PR against master branch?
we usually merge to master and cherry pick to other branches.
The script does it automatically

[eolivelli]

@lhotari we should also investigate why stream tests are not running on CI

[dlg99]

@eolivelli stream tests need "-DstreamTests" flag to run as defined in pom; while stream/statelib/ tests are fast, full stream/ test run (includes distributed logs) takes a lot of time, I guess they were disabled by default to speed the build up.

[eolivelli]

We should add a new CI workflow to run stream tests (as part of another PR).
I can do it tomorrow if you prefer. Thanks for the pointer