Load predefined symbols address via Thread.

runtime/vm/intermediate_language_arm.cc

Index: runtime/vm/intermediate_language_arm.cc
diff --git a/runtime/vm/intermediate_language_arm.cc b/runtime/vm/intermediate_language_arm.cc
index c81656105336ab8e166d9013cf971a72162bcfdb..35b3d7163a9aaba3564da538babe39b77a148dda 100644
--- a/runtime/vm/intermediate_language_arm.cc
+++ b/runtime/vm/intermediate_language_arm.cc
@@ -997,8 +997,7 @@ void StringFromCharCodeInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
   const Register char_code = locs()->in(0).reg();
   const Register result = locs()->out(0).reg();
 
-  ExternalLabel label(reinterpret_cast<uword>(Symbols::PredefinedAddress()));
-  __ LoadExternalLabel(result, &label, kNotPatchable);
+  __ ldr(result, Address(THR, Thread::predefined_symbols_address_offset()));
   __ AddImmediate(result, Symbols::kNullCharCodeSymbolOffset * kWordSize);
   __ ldr(result, Address(result, char_code, LSL, 1));  // Char code is a smi.
 }