JDK 9 RFR of JDK-8023898: Consolidate Map tests Collisions and InPlaceOpsCollisions into general Map-based test

[Amy Lu]

Please review this test refactoring to map test Collisions and 
InPlaceOpsCollisions.

These tests have (almost) same code for creating test data, and the test 
data can be reused cross tests. With converting to testng, test data 
creating is now done and provided by MapWithCollisionsProviders.java, 
and each test now uses explicit data provider, which makes test more clear.

Other changes include:
* Removed the redundant test Collections.testContainsKey and unnecessary 
map size check in the beginning of each test.
* Replaced 'check' with testng assertion method.
* Renaming and reformatting to make it more clear.

bug:https://bugs.openjdk.java.net/browse/JDK-8023898
webrev:http://cr.openjdk.java.net/~amlu/8023898/webrev.01/

Thanks,
Amy