[intrinsics] Drop the now obsolete %_DoubleHi and %_DoubleLo intrinsics.

src/crankshaft/arm64/lithium-arm64.cc

Index: src/crankshaft/arm64/lithium-arm64.cc
diff --git a/src/crankshaft/arm64/lithium-arm64.cc b/src/crankshaft/arm64/lithium-arm64.cc
index 9a0a7c4730187a8e6670b1aaa498b4de42e1d5b5..e1e0f82bd8dd508f9c8ec63981ff8d5a0e5b7ca6 100644
--- a/src/crankshaft/arm64/lithium-arm64.cc
+++ b/src/crankshaft/arm64/lithium-arm64.cc
@@ -1912,13 +1912,6 @@ LInstruction* LChunkBuilder::DoPushArguments(HPushArguments* instr) {
 }
 
 
-LInstruction* LChunkBuilder::DoDoubleBits(HDoubleBits* instr) {
-  HValue* value = instr->value();
-  DCHECK(value->representation().IsDouble());
-  return DefineAsRegister(new(zone()) LDoubleBits(UseRegister(value)));
-}
-
-
 LInstruction* LChunkBuilder::DoReturn(HReturn* instr) {
   LOperand* context = info()->IsStub()
       ? UseFixed(instr->context(), cp)