[es2015] Precompute the descriptive string for symbols.

src/builtins/arm64/builtins-arm64.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #if V8_TARGET_ARCH_ARM64
 
 #include "src/arm64/frames-arm64.h"
 #include "src/arm64/macro-assembler-arm64-inl.h"
 #include "src/codegen.h"
 #include "src/counters.h"
@@ skipping 280 matching lines @@
     __ SmiTag(x2);
     __ EnterBuiltinFrame(cp, x1, x2);
     __ Call(masm->isolate()->builtins()->ToString(), RelocInfo::CODE_TARGET);
     __ LeaveBuiltinFrame(cp, x1, x2);
     __ SmiUntag(x2);
   }
   __ b(&drop_frame_and_ret);
 
   // 3b. Convert symbol in x0 to a string.
   __ Bind(&symbol_descriptive_string);
-  {
-    __ Drop(x2);
-    __ Drop(1);
-    __ Push(x0);
-    __ TailCallRuntime(Runtime::kSymbolDescriptiveString);
-  }
+  __ Ldr(x0, FieldMemOperand(x0, Symbol::kDescriptiveStringOffset));
+  // Fall through.
 
   __ bind(&drop_frame_and_ret);
   {
     __ Drop(x2);
     __ Drop(1);
     __ Ret();
   }
 }
 
 // static
@@ skipping 2897 matching lines @@
   // Now jump to the instructions of the returned code object.
   __ Jump(x8);
 }
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_ARM