[Interpreter] Add ForInPrepare runtime function which returns a ObjectTriple.

src/compiler/linkage.cc

Index: src/compiler/linkage.cc
diff --git a/src/compiler/linkage.cc b/src/compiler/linkage.cc
index 87f33b6a656c69f781e064be55d2751d825282ac..8c49b54b19ae370b839cffa2c88b31234d29d600 100644
--- a/src/compiler/linkage.cc
+++ b/src/compiler/linkage.cc
@@ -243,6 +243,9 @@ CallDescriptor* Linkage::GetRuntimeCallDescriptor(
   if (locations.return_count_ > 1) {
     locations.AddReturn(regloc(kReturnRegister1));
   }
+  if (locations.return_count_ > 2) {
+    locations.AddReturn(regloc(kReturnRegister2));
+  }
   for (size_t i = 0; i < return_count; i++) {
     types.AddReturn(MachineType::AnyTagged());
   }
@@ -449,6 +452,9 @@ CallDescriptor* Linkage::GetStubCallDescriptor(
   if (locations.return_count_ > 1) {
     locations.AddReturn(regloc(kReturnRegister1));
   }
+  if (locations.return_count_ > 2) {
+    locations.AddReturn(regloc(kReturnRegister2));
+  }
   for (size_t i = 0; i < return_count; i++) {
     types.AddReturn(return_type);
   }