Add support for IncrementCounter in Hydrogen.

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 1f1098e0cf3cdc4d4b69ef3e10e7cf6ab7999485..e856100cc91d3f41c12a19738774967b907ce1e6 100644
--- a/src/x64/lithium-x64.cc
+++ b/src/x64/lithium-x64.cc
@@ -1995,6 +1995,8 @@ LInstruction* LChunkBuilder::DoConstant(HConstant* instr) {
   } else if (r.IsDouble()) {
     LOperand* temp = TempRegister();
     return DefineAsRegister(new(zone()) LConstantD(temp));
+  } else if (r.IsExternal()) {
+    return DefineAsRegister(new(zone()) LConstantE);
   } else if (r.IsTagged()) {
     return DefineAsRegister(new(zone()) LConstantT);
   } else {