Merge OpenJDK 8 java.net (part 2)

Partial import of upstream jdk8u60 that does not introduce behavioural                                            
differences:
 * Remove unused imports
 * Remove unused private fields
 * Adding final modifier to some private fields
 * Update copyright header
 * Use of generics
 * Cosmetic changes
 
This also imports upstream change to remove NetUtils, which does not
change behavior for Android as we does not use SecurityManager.

No functional change.                                                                                                         

Bug: 29067535                                                                                
Test: CTS java.net tests                                                             
Change-Id: I5c864a77f384f237ddac77d8c4579b291dcddb6b
30 files changed