[builtins] Remove some (now) unused code from C++ builtin adaptor.

src/arm/builtins-arm.cc

Index: src/arm/builtins-arm.cc
diff --git a/src/arm/builtins-arm.cc b/src/arm/builtins-arm.cc
index 723587704c3e9b5210c109add473397bd431f54e..a2d5f75709451c4300d72a164292bb77e760eb53 100644
--- a/src/arm/builtins-arm.cc
+++ b/src/arm/builtins-arm.cc
@@ -22,8 +22,6 @@ void Builtins::Generate_Adaptor(MacroAssembler* masm,
                                 BuiltinExtraArguments extra_args) {
   // ----------- S t a t e -------------
   //  -- r0                 : number of arguments excluding receiver
-  //                          (only guaranteed when the called function
-  //                           is not marked as DontAdaptArguments)
   //  -- r1                 : called function
   //  -- sp[0]              : last argument
   //  -- ...
@@ -32,13 +30,6 @@ void Builtins::Generate_Adaptor(MacroAssembler* masm,
   // -----------------------------------
   __ AssertFunction(r1);
 
-  // Make sure we operate in the context of the called function (for example
-  // ConstructStubs implemented in C++ will be run in the context of the caller
-  // instead of the callee, due to the way that [[Construct]] is defined for
-  // ordinary functions).
-  // TODO(bmeurer): Can we make this more robust?
-  __ ldr(cp, FieldMemOperand(r1, JSFunction::kContextOffset));
-
   // Insert extra arguments.
   int num_extra_args = 0;
   if (extra_args == NEEDS_CALLED_FUNCTION) {
@@ -49,15 +40,7 @@ void Builtins::Generate_Adaptor(MacroAssembler* masm,
   }
 
   // JumpToExternalReference expects r0 to contain the number of arguments
-  // including the receiver and the extra arguments.  But r0 is only valid
-  // if the called function is marked as DontAdaptArguments, otherwise we
-  // need to load the argument count from the SharedFunctionInfo.
-  __ ldr(r2, FieldMemOperand(r1, JSFunction::kSharedFunctionInfoOffset));
-  __ ldr(r2,
-         FieldMemOperand(r2, SharedFunctionInfo::kFormalParameterCountOffset));
-  __ SmiUntag(r2);
-  __ cmp(r2, Operand(SharedFunctionInfo::kDontAdaptArgumentsSentinel));
-  __ mov(r0, r2, LeaveCC, ne);
+  // including the receiver and the extra arguments.
   __ add(r0, r0, Operand(num_extra_args + 1));
 
   __ JumpToExternalReference(ExternalReference(id, masm->isolate()));