DRILL-7994: Dependency version updates for severe vulnerabilities (#2432)
* Sev 8+ vuln dep updates.
* Adjust netty-tcnative version for windows-x86_64.
* Bump Avro because of severe Velocity vulns.
* Adjust expected row count to accommodate t-digest 3.3 improvements.
"The meaning of the compression parameter became a bit more strict in this
latest version. As such, the digest should be a bit smaller and tails
should be a bit more accurate." -- Ted Dunning
* Code comment whitespace formatting.
* Remove cruft from jdbc-all jar.
* Return needed Netty jars to jdbc-all.
* Adjust unit test memory allocs for TestAggregateFunctions.
* Remove references to unused artifact jersey-guava.
* Netty to 2.0.48.
* +200MiB direct memory for the unit test run.
* Upgrade jetty-server and h2 for dependabot.
* Fixes for H2 lib upgrade.
* Work around DOUBLE type DDL syntax error for pg dialect.
* Increase CI heap mem allocation for the sake of JDK 8.
* Specify parallel GC for CI to try to minimise peak mem usage.
* Cast Netty ByteBuffer to Buffer for JDK 8 compat.
* Increase CI heap mem allocation for the sake of TestAggregateFunctions.
