[Interpreter] Add support for calling runtime functions which return a pair.

test/unittests/interpreter/bytecode-array-builder-unittest.cc

Index: test/unittests/interpreter/bytecode-array-builder-unittest.cc
diff --git a/test/unittests/interpreter/bytecode-array-builder-unittest.cc b/test/unittests/interpreter/bytecode-array-builder-unittest.cc
index 5f2a8d723d02662b5a835ef8d88f7216749f070e..504a05c21d3afddbe05b8a1d28e4ebc3330db397 100644
--- a/test/unittests/interpreter/bytecode-array-builder-unittest.cc
+++ b/test/unittests/interpreter/bytecode-array-builder-unittest.cc
@@ -109,6 +109,7 @@ TEST_F(BytecodeArrayBuilderTest, AllBytecodesGenerated) {
   builder.Call(reg, reg, 0, 0)
       .Call(reg, reg, 0, 1024)
       .CallRuntime(Runtime::kIsArray, reg, 1)
+      .CallRuntimeForPair(Runtime::kLoadLookupSlot, reg, 1, reg)
       .CallJSRuntime(Context::SPREAD_ITERABLE_INDEX, reg, 1);
 
   // Emit binary operator invocations.