Log all the error in the GarbageCollectorThread

[zymap]

Motivation

We met the GarbageCollectionThread was stopped by some runtime error, but we didn't catch it then, causing the GC to stop.
Such as:
#3901
#4544

In our case, the GC stopped because of the OutOfDirectMemoryException then the process stopped and the files can not be deleted. But we didn't see any error logs. This PR enhance the log info when an unhandled error happens.
We already have the PR fixed that.

And another fix in this PR is to change the Exception to the Throwable in the getEntryLogMetadata.

Here is the error stack:

    io.netty.util.internal.OutOfDirectMemoryError: failed to allocate 213909504 byte(s) of direct memory (used: 645922847, max: 858783744)
	at io.netty.util.internal.PlatformDependent.incrementMemoryCounter(PlatformDependent.java:880)
	at io.netty.util.internal.PlatformDependent.allocateDirectNoCleaner(PlatformDependent.java:809)
	at io.netty.buffer.PoolArena$DirectArena.allocateDirect(PoolArena.java:718)
	at io.netty.buffer.PoolArena$DirectArena.newUnpooledChunk(PoolArena.java:707)
	at io.netty.buffer.PoolArena.allocateHuge(PoolArena.java:224)
	at io.netty.buffer.PoolArena.allocate(PoolArena.java:142)
	at io.netty.buffer.PoolArena.reallocate(PoolArena.java:317)
	at io.netty.buffer.PooledByteBuf.capacity(PooledByteBuf.java:123)
	at io.netty.buffer.AbstractByteBuf.ensureWritable0(AbstractByteBuf.java:305)
	at io.netty.buffer.AbstractByteBuf.ensureWritable(AbstractByteBuf.java:280)
	at io.netty.buffer.AbstractByteBuf.writeBytes(AbstractByteBuf.java:1103)
	at org.apache.bookkeeper.bookie.BufferedReadChannel.read(BufferedReadChannel.java:104)
	at org.apache.bookkeeper.bookie.DefaultEntryLogger.extractEntryLogMetadataFromIndex(DefaultEntryLogger.java:1109)
	at org.apache.bookkeeper.bookie.DefaultEntryLogger.getEntryLogMetadata(DefaultEntryLogger.java:1060)
	at org.apache.bookkeeper.bookie.GarbageCollectorThread.extractMetaFromEntryLogs(GarbageCollectorThread.java:678)
	at org.apache.bookkeeper.bookie.GarbageCollectorThread.runWithFlags(GarbageCollectorThread.java:365)
	at org.apache.bookkeeper.bookie.GarbageCollectorThread.lambda$triggerGC$4(GarbageCollectorThread.java:268)
	at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
	at java.base/java.util.concurrent.FutureTask.run(Unknown Source)
	at java.base/java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(Unknown Source)
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
	at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
	at java.base/java.lang.Thread.run(Unknown Source)

You can see it get much more memory used here extractEntryLogMetadataFromIndex(DefaultEntryLogger.java:1109). The reason is that the header has the wrong data of the header, which should already be fixed by #4607. Then it reading with a wrong map size which could take a lot of memory.