Unify SoftDeoptimize and Deoptimize hydrogen instructions

src/x64/lithium-x64.cc

Index: src/x64/lithium-x64.cc
diff --git a/src/x64/lithium-x64.cc b/src/x64/lithium-x64.cc
index 2cec68b097573eab83f941c03940b01647f2e3e9..1144f1cad966f5a872a91d538152e810aaf9328e 100644
--- a/src/x64/lithium-x64.cc
+++ b/src/x64/lithium-x64.cc
@@ -710,11 +710,6 @@ LInstruction* LChunkBuilder::DoEnvironmentMarker(HEnvironmentMarker* instr) {
 }
 
 
-LInstruction* LChunkBuilder::DoSoftDeoptimize(HSoftDeoptimize* instr) {
-  return AssignEnvironment(new(zone()) LDeoptimize);
-}
-
-
 LInstruction* LChunkBuilder::DoDeoptimize(HDeoptimize* instr) {
   return AssignEnvironment(new(zone()) LDeoptimize);
 }