Bump virtual register width in LUnallocated.

R=svenpanne@chromium.org

Review URL: https://codereview.chromium.org/14589008

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@14516 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/lithium.h

@@ -182,8 +182,7 @@ class LUnallocated: public LOperand {
 
   // BitFields for all unallocated operands.
   class BasicPolicyField     : public BitField<BasicPolicy,     3,  1> {};
-  // TODO(mstarzinger): Bump this from 15 bit to 18 bit in a follow-up CL.
-  class VirtualRegisterField : public BitField<unsigned,        4, 15> {};
+  class VirtualRegisterField : public BitField<unsigned,        4, 18> {};
 
   // BitFields specific to BasicPolicy::FIXED_SLOT.
   class FixedSlotIndexField  : public BitField<int,            22, 10> {};