Remove high promotion mode.

src/x64/macro-assembler-x64.cc

Index: src/x64/macro-assembler-x64.cc
diff --git a/src/x64/macro-assembler-x64.cc b/src/x64/macro-assembler-x64.cc
index 8bd08d370bee418ed2083250918f0ebbfaea84b8..6873efff67d39f7a948b634b24c4f9c768a79c30 100644
--- a/src/x64/macro-assembler-x64.cc
+++ b/src/x64/macro-assembler-x64.cc
@@ -4560,33 +4560,12 @@ void MacroAssembler::AllocateAsciiConsString(Register result,
                                              Register scratch1,
                                              Register scratch2,
                                              Label* gc_required) {
-  Label allocate_new_space, install_map;
-  AllocationFlags flags = TAG_OBJECT;
-
-  ExternalReference high_promotion_mode = ExternalReference::
-      new_space_high_promotion_mode_active_address(isolate());
-
-  Load(scratch1, high_promotion_mode);
-  testb(scratch1, Immediate(1));
-  j(zero, &allocate_new_space);
   Allocate(ConsString::kSize,
            result,
            scratch1,
            scratch2,
            gc_required,
-           static_cast<AllocationFlags>(flags | PRETENURE_OLD_POINTER_SPACE));
-
-  jmp(&install_map);
-
-  bind(&allocate_new_space);
-  Allocate(ConsString::kSize,
-           result,
-           scratch1,
-           scratch2,
-           gc_required,
-           flags);
-
-  bind(&install_map);
+           TAG_OBJECT);
 
   // Set the map. The other fields are left uninitialized.
   LoadRoot(kScratchRegister, Heap::kConsAsciiStringMapRootIndex);