Introduce StackOperandForReturnAddress operand for X64 to access return address in the stack

src/x64/macro-assembler-x64.h

Index: src/x64/macro-assembler-x64.h
diff --git a/src/x64/macro-assembler-x64.h b/src/x64/macro-assembler-x64.h
index 9d5d2a31c5ceee61652cd923ca83e8a13d1388ca..e611c8ae27999a9520d0aa07bfa050b51a0bb831 100644
--- a/src/x64/macro-assembler-x64.h
+++ b/src/x64/macro-assembler-x64.h
@@ -1518,6 +1518,10 @@ inline Operand StackSpaceOperand(int index) {
 }
 
 
+inline Operand StackOperandForReturnAddress(int32_t disp) {
+  return Operand(rsp, disp);
+}
+
 
 #ifdef GENERATED_CODE_COVERAGE
 extern void LogGeneratedCodeCoverage(const char* file_line);