RFR (M) #4 CR 8003985: Support @Contended annotation

[Aleksey Shipilev]

Hi,

This is the final call for reviews for @Contended:
  http://cr.openjdk.java.net/~shade/8003985/webrev.00/

Testing:
 - Test8003985 passes on Linux x86_64
 - JPRT full cycle passed
 - VM adhoc tests are underway, but should be the same as previous
passed run, since there are no semantical changes

JEP-142 is in Funded state:
 http://openjdk.java.net/jeps/142

Thanks,
Aleksey.