Reduce verbosity of direct runner

It appears as though https://github.com/apache/beam/pull/12519 has increased the volume of Java Precommit warning output ~4x.

https://ci-beam.apache.org/job/beam_PreCommit_Java_Cron/3124 lists this as the single change.

Console output for previous build is 3MB: https://ci-beam.apache.org/job/beam_PreCommit_Java_Cron/3123/console
Console output for this build is 13MB: https://ci-beam.apache.org/job/beam_PreCommit_Java_Cron/3124/consoleFull

and has lots of entries like:

17:13:30 WARNING: Coder of type class org.apache.beam.sdk.coders.KvCoder has a #structuralValue method which does not return true when the encoding of the elements is equal. Element KV{[67, -53, -64, -6, 101, -59, 69, 36, 85, -98, 87, -102, 85, -46, 18, -108, 46, -45, -68, 64, -13, 60, -114, -76, 11, 114, 96, -7, 67, -37, -114, -85, 76, 57, -29, 99, -25, -69, 56, -122, -7, 19, -17, -93, 32, 74, -22, 95, 68, 13, -113, 121, 95, 9, 31, 99, -112, 27, 79, -29, -48, -65, -100, -4, -75, -81, 56, 13, -112, 20, 116, 89, 53, 28, 118, -2, -59, 93, -17, 1, 0, 56, 91, 9, -71, 6, 127, 65, 5, 9, -57, -59, 119, 31, -92, 34, -96, -118, -49, -60, 4, 36, 90, 97, 7, 7, 59, -90, -87, 107, -124, 31, 50, 101, -127, -28, -31, 0, 77, -82, 91, -98, 33, -16, 15, 23, 21, 120], KV

}