[turbofan] Add support for relevant ES6 type conversion intrinsics.

src/compiler/operator-properties.cc

Index: src/compiler/operator-properties.cc
diff --git a/src/compiler/operator-properties.cc b/src/compiler/operator-properties.cc
index 7f8a2b3852948eba16c3fb314136b929254e5d44..d1bea560916404ea913ca79051796a4f8e0b49f4 100644
--- a/src/compiler/operator-properties.cc
+++ b/src/compiler/operator-properties.cc
@@ -59,9 +59,10 @@ int OperatorProperties::GetFrameStateInputCount(const Operator* op) {
     case IrOpcode::kJSCreateWithContext:
 
     // Conversions
-    case IrOpcode::kJSToObject:
-    case IrOpcode::kJSToNumber:
     case IrOpcode::kJSToName:
+    case IrOpcode::kJSToNumber:
+    case IrOpcode::kJSToObject:
+    case IrOpcode::kJSToString:
 
     // Misc operations
     case IrOpcode::kJSConvertReceiver: