[strong] Implement strong mode semantics for the count operation.

src/runtime/runtime-internal.cc

Index: src/runtime/runtime-internal.cc
diff --git a/src/runtime/runtime-internal.cc b/src/runtime/runtime-internal.cc
index becd2f0e4fa7b265278bfc67824e8ed6b863b1ae..290d7af2fae113949d0394e6fad32de882747a65 100644
--- a/src/runtime/runtime-internal.cc
+++ b/src/runtime/runtime-internal.cc
@@ -103,6 +103,14 @@ RUNTIME_FUNCTION(Runtime_ThrowIteratorResultNotAnObject) {
 }
 
 
+RUNTIME_FUNCTION(Runtime_ThrowStrongModeImplicitConversion) {
+  HandleScope scope(isolate);
+  DCHECK(args.length() == 0);
+  THROW_NEW_ERROR_RETURN_FAILURE(
+      isolate, NewTypeError(MessageTemplate::kStrongImplicitConversion));
+}
+
+
 RUNTIME_FUNCTION(Runtime_PromiseRejectEvent) {
   DCHECK(args.length() == 3);
   HandleScope scope(isolate);