PPC64 (part 114/120): Support for Call nodes with constants.

C2 Call nodes use several constant values. So far C2 does not
support placing these values in the constant table of the nmethod.

Among others, these constants are
 - the called address
 - the inline cache
 - values required by the C-calling convention (on PPC, env pointer
   and toc from function descriptor)

This change extends Call nodes so that they can issue constants
to the constant table.

- Extend adlc to add edge to MachConstantBaseNode if
  $constanttablebase is used in the specification.
- Extend Call nodes to deliver proper register mask to
  register allocation for this new input.
- Add method ins_num_consts() so that number of required
  constants can be specified in the call node.
- Extend output() so that it reserves space for the
  constants in the Calls, using ins_num_consts().


----------------------------

This is preparation for PPC64 integration: http://openjdk.java.net/jeps/175
This and following ppc64 changes will go into staging repository first and tested there: http://hg.openjdk.java.net/ppc-aix-port/stage/

As we basically redesigned this, it comprises two of the original patches:
http://hg.openjdk.java.net/ppc-aix-port/jdk8/hotspot/file/338e318f1e12/ppc_patches/0114_opto-hook_to_postprocess_matcher_output_platform_dependent.patch
http://hg.openjdk.java.net/ppc-aix-port/jdk8/hotspot/file/338e318f1e12/ppc_patches/0120_opto-constants_for_Call_nodes.patch