[builtins] Move DCHECK under drop_jsargs

Port: c69b0c80

Change-Id: Ie29079f976c7ab6fa14e5edc1da296a9e75b1bcf
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3523822Reviewed-by: Junliang Yan <junyan@redhat.com>
Commit-Queue: Milad Farazmand <mfarazma@redhat.com>
Cr-Commit-Position: refs/heads/main@{#79471}

src/compiler/backend/ppc/code-generator-ppc.cc

@@ -4161,8 +4161,6 @@ void CodeGenerator::AssembleReturn(InstructionOperand* additional_pop_count) {
 
   unwinding_info_writer_.MarkBlockWillExit();
 
-  // We might need r6 for scratch.
-  DCHECK(!call_descriptor->CalleeSavedRegisters().has(r6));
   PPCOperandConverter g(this, nullptr);
   const int parameter_slots =
       static_cast<int>(call_descriptor->ParameterSlotCount());
@@ -4215,6 +4213,7 @@ void CodeGenerator::AssembleReturn(InstructionOperand* additional_pop_count) {
     // The number of arguments without the receiver is
     // max(argc_reg, parameter_slots-1), and the receiver is added in
     // DropArguments().
+    DCHECK(!call_descriptor->CalleeSavedRegisters().has(argc_reg));
     if (parameter_slots > 1) {
       Label skip;
       __ CmpS64(argc_reg, Operand(parameter_slots), r0);

src/compiler/backend/s390/code-generator-s390.cc

@@ -3519,8 +3519,6 @@ void CodeGenerator::AssembleReturn(InstructionOperand* additional_pop_count) {
 
   unwinding_info_writer_.MarkBlockWillExit();
 
-  // We might need r3 for scratch.
-  DCHECK(!call_descriptor->CalleeSavedRegisters().has(r5));
   S390OperandConverter g(this, nullptr);
   const int parameter_slots =
       static_cast<int>(call_descriptor->ParameterSlotCount());
@@ -3572,6 +3570,7 @@ void CodeGenerator::AssembleReturn(InstructionOperand* additional_pop_count) {
     // The number of arguments without the receiver is
     // max(argc_reg, parameter_slots-1), and the receiver is added in
     // DropArguments().
+    DCHECK(!call_descriptor->CalleeSavedRegisters().has(argc_reg));
     if (parameter_slots > 1) {
       Label skip;
       __ CmpS64(argc_reg, Operand(parameter_slots));