Block Validation Errors should be at least INFO level not DEBUG or TRACE

[shemnon]

When importing a chain the errors causing a block to be rejected should be at INFO. Currently they are at DEBUG or TRACE. Bad blocks are rare enough and critical enough they should not be veiled behind developer flags.

Expected behavior: [What you expect to happen]

stack traces that look like

2020-11-16 11:56:01.310+10:00 | EthScheduler-Services-5 (importBlock) | INFO  | CalculatedDifficultyValidationRule | Invalid block header: difficulty 1 does not equal expected difficulty 2
2020-11-16 11:56:03.320+10:00 | EthScheduler-Timer-0 | INFO  | FullSyncTargetManager | No sync target, waiting for peers: 0

Actual behavior:
Stack traces that look like this

2020-11-16 11:56:01.310+10:00 | EthScheduler-Services-5 (importBlock) | WARN  | PipelineChainDownloader | Chain download failed. Restarting after short delay.
java.util.concurrent.CompletionException: org.hyperledger.besu.ethereum.eth.sync.tasks.exceptions.InvalidBlockException: Failed to import block: Invalid block at #7 (0xd169d7c49653f7070fc8a8e45af477c8efd6840279f5fc5277a2359a37afe88d)
	at java.util.concurrent.CompletableFuture.encodeRelay(CompletableFuture.java:367) ~[?:?]
	at java.util.concurrent.CompletableFuture.completeRelay(CompletableFuture.java:376) ~[?:?]
	at java.util.concurrent.CompletableFuture$UniRelay.tryFire(CompletableFuture.java:1019) ~[?:?]
	at java.util.concurrent.CompletableFuture.postComplete(CompletableFuture.java:506) ~[?:?]
	at java.util.concurrent.CompletableFuture.completeExceptionally(CompletableFuture.java:2088) ~[?:?]
	at org.hyperledger.besu.services.pipeline.Pipeline.abort(Pipeline.java:152) ~[besu-pipeline-1.5.0.jar:1.5.0]
	at org.hyperledger.besu.services.pipeline.Pipeline.lambda$runWithErrorHandling$3(Pipeline.java:134) ~[besu-pipeline-1.5.0.jar:1.5.0]
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:515) [?:?]
	at java.util.concurrent.FutureTask.run(FutureTask.java:264) [?:?]
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128) [?:?]
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628) [?:?]
	at java.lang.Thread.run(Thread.java:834) [?:?]
Caused by: org.hyperledger.besu.ethereum.eth.sync.tasks.exceptions.InvalidBlockException: Failed to import block: Invalid block at #7 (0xd169d7c49653f7070fc8a8e45af477c8efd6840279f5fc5277a2359a37afe88d)
	at org.hyperledger.besu.ethereum.eth.sync.fullsync.FullImportBlockStep.accept(FullImportBlockStep.java:57) ~[besu-eth-1.5.0.jar:1.5.0]
	at org.hyperledger.besu.ethereum.eth.sync.fullsync.FullImportBlockStep.accept(FullImportBlockStep.java:30) ~[besu-eth-1.5.0.jar:1.5.0]
	at org.hyperledger.besu.services.pipeline.CompleterStage.run(CompleterStage.java:37) ~[besu-pipeline-1.5.0.jar:1.5.0]
	at org.hyperledger.besu.services.pipeline.Pipeline.lambda$runWithErrorHandling$3(Pipeline.java:130) ~[besu-pipeline-1.5.0.jar:1.5.0]
	... 5 more
2020-11-16 11:56:03.320+10:00 | EthScheduler-Timer-0 | INFO  | FullSyncTargetManager | No sync target, waiting for peers: 0