RFR(XXS): 8141146: Add Error hierarchy to test library

[Kirill Zhaldybin]

Hi,

Could somebody please review this change?
It adds EnvironmentIssue and TestBug classes for environment issue and 
test bug correspondingly to the test library.
It is the first part of JDK-8065651: Enhance Asserts to throw different 
exceptions for different types of assertions.

CR: https://bugs.openjdk.java.net/browse/JDK-8141146
WebRev: http://cr.openjdk.java.net/~kzhaldyb/webrevs/JDK-8141146/webrev.00/

Thank you.

Regards, Kirill