[builtins] fix mapcheck in Array.includes fast-case when searching for String

src/builtins/builtins-array.cc

Index: src/builtins/builtins-array.cc
diff --git a/src/builtins/builtins-array.cc b/src/builtins/builtins-array.cc
index 888eaef280f821e723435327f1116e4203de86b5..479d08c583f4a302daa262290c4ae8fdcbe87e84 100644
--- a/src/builtins/builtins-array.cc
+++ b/src/builtins/builtins-array.cc
@@ -1517,7 +1517,7 @@ void Builtins::Generate_ArrayIncludes(CodeStubAssembler* assembler) {
           assembler->LoadFixedArrayElement(elements, index_var.value());
       assembler->GotoIf(assembler->WordIsSmi(element_k), &continue_loop);
       assembler->GotoUnless(assembler->Int32LessThan(
-                                assembler->LoadMapInstanceType(element_k),
+                                assembler->LoadInstanceType(element_k),
                                 assembler->Int32Constant(FIRST_NONSTRING_TYPE)),
                             &continue_loop);