JanusGraph image stop responding after query timeout

I'm using the default docker image janusgraph/janusgraph:latest (Berkeley and Lucene)
and connecting with gremlin console.

When JanusGraph server exceeded his 'evaluationTimeout' the server stop responding

server error:
```
java.util.concurrent.TimeoutException: Evaluation exceeded the configured 'evaluationTimeout' threshold of 30000 ms or evaluation was otherwise cancelled directly for request [g.V()]
at org.apache.tinkerpop.gremlin.groovy.engine.GremlinExecutor.lambda$eval$1(GremlinExecutor.java:316)
at io.netty.util.concurrent.PromiseTask.runTask(PromiseTask.java:98)
at io.netty.util.concurrent.ScheduledFutureTask.run(ScheduledFutureTask.java:170)
at io.netty.util.concurrent.AbstractEventExecutor.safeExecute(AbstractEventExecutor.java:164)
at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:472)
at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:500)
at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:989)
at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)
at java.lang.Thread.run(Thread.java:748)
1318978 [pool-6-thread-1] WARN org.janusgraph.diskstorage.log.kcvs.KCVSLog - Could not read messages for timestamp [2020-05-24T10:12:30.449Z] (this read will be retried)
org.janusgraph.core.JanusGraphException: Could not execute operation due to backend exception
at org.janusgraph.diskstorage.util.BackendOperation.execute(BackendOperation.java:56)
at org.janusgraph.diskstorage.util.BackendOperation.execute(BackendOperation.java:158)
at org.janusgraph.diskstorage.log.kcvs.KCVSLog$MessagePuller.run(KCVSLog.java:725)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:308)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(ScheduledThreadPoolExecutor.java:180)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:294)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at java.lang.Thread.run(Thread.java:748)
Caused by: org.janusgraph.diskstorage.PermanentBackendException: Could not start BerkeleyJE transaction
at org.janusgraph.diskstorage.berkeleyje.BerkeleyJEStoreManager.beginTransaction(BerkeleyJEStoreManager.java:163)
at org.janusgraph.diskstorage.berkeleyje.BerkeleyJEStoreManager.beginTransaction(BerkeleyJEStoreManager.java:47)
at org.janusgraph.diskstorage.keycolumnvalue.keyvalue.OrderedKeyValueStoreManagerAdapter.beginTransaction(OrderedKeyValueStoreManagerAdapter.java:68)
at org.janusgraph.diskstorage.log.kcvs.KCVSLog.openTx(KCVSLog.java:319)
at org.janusgraph.diskstorage.util.BackendOperation.execute(BackendOperation.java:145)
at org.janusgraph.diskstorage.util.BackendOperation$1.call(BackendOperation.java:161)
at org.janusgraph.diskstorage.util.BackendOperation.executeDirect(BackendOperation.java:68)
at org.janusgraph.diskstorage.util.BackendOperation.execute(BackendOperation.java:54)
... 9 more
Caused by: com.sleepycat.je.ThreadInterruptedException: (JE 18.3.12) Environment must be closed, caused by: com.sleepycat.je.ThreadInterruptedException: Environment invalid because of previous exception: (JE 18.3.12) /var/lib/janusgraph/data java.lang.InterruptedException THREAD_INTERRUPTED: InterruptedException may cause incorrect internal state, unable to continue. Environment is invalid and must be closed.
at com.sleepycat.je.ThreadInterruptedException.wrapSelf(ThreadInterruptedException.java:105)
at com.sleepycat.je.dbi.EnvironmentImpl.checkIfInvalid(EnvironmentImpl.java:1835)
at com.sleepycat.je.dbi.EnvironmentImpl.checkOpen(EnvironmentImpl.java:1844)
at com.sleepycat.je.Environment.checkOpen(Environment.java:2697)
at com.sleepycat.je.Environment.beginTransactionInternal(Environment.java:1409)
at com.sleepycat.je.Environment.beginTransaction(Environment.java:1383)
at org.janusgraph.diskstorage.berkeleyje.BerkeleyJEStoreManager.beginTransaction(BerkeleyJEStoreManager.java:146)
... 16 more
Caused by: com.sleepycat.je.ThreadInterruptedException: Environment invalid because of previous exception: (JE 18.3.12) /var/lib/janusgraph/data java.lang.InterruptedException THREAD_INTERRUPTED: InterruptedException may cause incorrect internal state, unable to continue. Environment is invalid and must be closed.
at com.sleepycat.je.latch.LatchImpl.acquireExclusive(LatchImpl.java:67)
at com.sleepycat.je.tree.IN.latch(IN.java:547)
at com.sleepycat.je.dbi.CursorImpl.latchBIN(CursorImpl.java:402)
at com.sleepycat.je.dbi.CursorImpl.cloneCursor(CursorImpl.java:230)
at com.sleepycat.je.Cursor.beginMoveCursor(Cursor.java:5252)
at com.sleepycat.je.Cursor.beginMoveCursor(Cursor.java:5259)
at com.sleepycat.je.Cursor.retrieveNextNoDups(Cursor.java:3550)
at com.sleepycat.je.Cursor.retrieveNext(Cursor.java:3312)
at com.sleepycat.je.Cursor.getInternal(Cursor.java:1313)
at com.sleepycat.je.Cursor.get(Cursor.java:1244)
at com.sleepycat.je.Cursor.getNext(Cursor.java:1512)

```
after the query been sent to server and timeout exceeded other queries which worked before gets same response

`Evaluation exceeded the configured 'evaluationTimeout' threshold of 30000 ms or evaluation was otherwise cancelled directly for request [g.V().limit(4).valueMap()]: null - try increasing the timeout with the :remote command`

Start by reproducing the timeout with the default janusgraph/janusgraph:latest image and the Gremlin request g.V(). Review GremlinExecutor timeout handling alongside BerkeleyJEStoreManager.beginTransaction and KCVSLog; done means a timed-out query does not invalidate the BerkeleyJE environment and subsequent queries continue to work.

Written by the indexing model from the issue text.