Add monomorphic CompareNilICs and Crankshaft support

src/lithium.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 311 matching lines @@
           LInstruction* cur = instructions()->at(i);
           if (cur->IsGap()) {
             LGap* gap = LGap::cast(cur);
             if (!gap->IsRedundant()) {
               can_eliminate = false;
             }
           } else {
             can_eliminate = false;
           }
         }
-
         if (can_eliminate) {
           label->set_replacement(GetLabel(goto_instr->block_id()));
         }
       }
     }
   }
 }
 
 
 void LChunk::AddInstruction(LInstruction* instr, HBasicBlock* block) {
@@ skipping 143 matching lines @@
       } else {
         spill_slot_count_++;
       }
     }
     iterator.Advance();
   }
 }
 
 
 } }  // namespace v8::internal