Prettier exception when backup target is different store
Merge pull request #3002 from lutovich/2.1-prettier-exception-in-backup

Prettier exception when backup target is different store
Remove artifacts from merge
Add missing code for closing the pageCache when used in migration/tools
Make CommandApplierFacade more generic.
Get exact count of number of nodes in the graph.
Get exact count of number of nodes with given label.
Get exact count of number of relationships in the graph.
Get exact count of number of relationships with given type.
Remove unused statistics service.
IdMapping interface for BatchImporter that makes sense

derived from actual use case. Although there's only one implementation,
which is to use the actual node ids provided directly from the input
entities.

Basically the changes consist of:

 * having InputEntity#id(), InputRelationship#startNode()/endNode() return Object
 * IdMapper has something closer to an index interface with put and get
 * IdMapping is provided to BatchImporter#doImport and couple an IdMapper
   and IdGenerator (batch import version of an id generator)
 * NodeStage uses IdMapper#put in conjunction with IdGenerator#generate and
   IdMapper#sort in the end
 * RelationshipStage calls IdMapper#get
Merge pull request #3063 from tinwelint/2.1-proper-id-mapper-interface

IdMapping interface for BatchImporter that makes sense
Add a test to confirm nameMatchPatternElements behaviour for parameters
Move the adversarial file system to the io module
Add a robustness test for the page caches

It uses the adversarial file system to throw lots of exceptions at the page cache implementations.
It currently fails. Badly.
Make the MuninnPageCache survive the adversarial file system

* Fix a bug in the AdversarialFSA where mischief might prevent client code from
  ever reading the last byte of a chunk into a buffer.
* The Muninn eviction thread now no longer dies if flushing on eviction throws
  an exception.
* This makes Muninn able to recover from arbitrary errors, should their cause
  disappear.
AdversarialFSA PageCacheTest

Increase failure probabilities and fix some of the failures in the StandardPageCache.
Not all of the failures are fixed, though, so the test is still failing.
It has therefore been ignored for now, because we want to get the fixes for Muninn into master as soon as possible.
retries around shared lock page access
test fix for page cache stress test
Merge remote-tracking branch 'upstream/2.1-maint' into 2.2-merge-2.1

Conflicts:
	community/consistency-check/src/test/java/org/neo4j/unsafe/impl/batchimport/ParallelBatchImporterTest.java
	community/cypher/cypher/src/test/scala/org/neo4j/cypher/internal/compiler/v2_2/SyntaxExceptionTest.scala
	community/kernel/src/main/java/org/neo4j/kernel/impl/storemigration/LogFiles.java
	community/kernel/src/main/java/org/neo4j/kernel/impl/storemigration/StoreMigrator.java
	community/kernel/src/main/java/org/neo4j/unsafe/impl/batchimport/ParallelBatchImporter.java
	community/kernel/src/main/java/org/neo4j/unsafe/impl/batchimport/RelationshipEncoderStep.java
	enterprise/backup/src/main/java/org/neo4j/backup/BackupImpl.java
	enterprise/backup/src/main/java/org/neo4j/backup/BackupService.java
	enterprise/backup/src/test/java/org/neo4j/backup/BackupServiceIT.java