Fix/unify root handling in code generation.

src/arm/macro-assembler-arm.cc

Index: src/arm/macro-assembler-arm.cc
diff --git a/src/arm/macro-assembler-arm.cc b/src/arm/macro-assembler-arm.cc
index b9728ed04fa14aab43229acbaba69d3181165c49..a56744bf597a245a0afed0b4b1a64b38d1a4cd0c 100644
--- a/src/arm/macro-assembler-arm.cc
+++ b/src/arm/macro-assembler-arm.cc
@@ -375,16 +375,13 @@ void MacroAssembler::LoadRoot(Register destination,
                               Heap::RootListIndex index,
                               Condition cond) {
   if (CpuFeatures::IsSupported(MOVW_MOVT_IMMEDIATE_LOADS) &&
-      !Heap::RootCanBeWrittenAfterInitialization(index) &&
+      isolate()->heap()->RootCanBeTreatedAsConstant(index) &&
       !predictable_code_size()) {
-    Handle<Object> root(isolate()->heap()->roots_array_start()[index],
-                        isolate());
-    if (!isolate()->heap()->InNewSpace(*root)) {
-      // The CPU supports fast immediate values, and this root will never
-      // change. We will load it as a relocatable immediate value.
-      mov(destination, Operand(root), LeaveCC, cond);
-      return;
-    }
+    // The CPU supports fast immediate values, and this root will never
+    // change. We will load it as a relocatable immediate value.
+    Handle<Object> root(&isolate()->heap()->roots_array_start()[index]);
+    mov(destination, Operand(root), LeaveCC, cond);
+    return;
   }
   ldr(destination, MemOperand(kRootRegister, index << kPointerSizeLog2), cond);
 }