IDL: Clean up argument conversion error handling

Source/bindings/tests/results/core/V8TestObject.cpp

Index: Source/bindings/tests/results/core/V8TestObject.cpp
diff --git a/Source/bindings/tests/results/core/V8TestObject.cpp b/Source/bindings/tests/results/core/V8TestObject.cpp
index 3b96f2ac4c4ecb6bf6fce37febb8b3421cf1a2ce..87298836b17007369a4930d579c747320847e931 100644
--- a/Source/bindings/tests/results/core/V8TestObject.cpp
+++ b/Source/bindings/tests/results/core/V8TestObject.cpp
@@ -5650,8 +5650,6 @@ static void voidMethodVoidCallbackFunctionArgMethod(const v8::FunctionCallbackIn
     TestObject* impl = V8TestObject::toImpl(info.Holder());
     ScriptValue voidCallbackFunctionArg;
     {
-        v8::TryCatch block;
-        V8RethrowTryCatchScope rethrow(block);
         voidCallbackFunctionArg = ScriptValue(ScriptState::current(info.GetIsolate()), info[0]);
     }
     impl->voidMethodVoidCallbackFunctionArg(voidCallbackFunctionArg);
@@ -5673,8 +5671,6 @@ static void voidMethodAnyCallbackFunctionOptionalAnyArgMethod(const v8::Function
     TestObject* impl = V8TestObject::toImpl(info.Holder());
     ScriptValue anyCallbackFunctionOptionalAnyArgArg;
     {
-        v8::TryCatch block;
-        V8RethrowTryCatchScope rethrow(block);
         anyCallbackFunctionOptionalAnyArgArg = ScriptValue(ScriptState::current(info.GetIsolate()), info[0]);
     }
     impl->voidMethodAnyCallbackFunctionOptionalAnyArg(anyCallbackFunctionOptionalAnyArgArg);