Initial runtime support for the ValueTypes attribute

[Frederic Parain]

Please review this first patch related to the ValueTypes attribute:

http://cr.openjdk.java.net/~fparain/VTAttribute/webrev.00/

The patch includes:
  - the parsing of the ValueTypes attribute
  - the creation of meta-data from this attribute
  - a consistency check between the ACC_FLATTENABLE flag
    and the ValueTypes attribute
  - the pre-loading of method arguments types and return values types

Fred