S390: Fix storing to below stack to avoid sampler handler corrupting stored value

src/s390/code-stubs-s390.cc

 // Copyright 2014 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_S390
 
 #include "src/code-stubs.h"
 #include "src/api-arguments.h"
 #include "src/base/bits.h"
 #include "src/bootstrapper.h"
@@ skipping 4242 matching lines @@
   // Function descriptor
   __ LoadP(ToRegister(ABI_TOC_REGISTER), MemOperand(ip, kPointerSize));
   __ LoadP(ip, MemOperand(ip, 0));
 // ip already set.
 #endif
 #endif
 
   // zLinux ABI requires caller's frame to have sufficient space for callee
   // preserved regsiter save area.
   __ LoadImmP(r0, Operand::Zero());
-  __ StoreP(r0, MemOperand(sp, -kCalleeRegisterSaveAreaSize -
-                                   kNumRequiredStackFrameSlots * kPointerSize));
   __ lay(sp, MemOperand(sp, -kCalleeRegisterSaveAreaSize -
                                 kNumRequiredStackFrameSlots * kPointerSize));
+  __ StoreP(r0, MemOperand(sp));
 #if defined(USE_SIMULATOR)
   // Under the simulator we need to indirect the entry hook through a
   // trampoline function at a known address.
   // It additionally takes an isolate as a third parameter
   __ mov(r4, Operand(ExternalReference::isolate_address(isolate())));
 
   ApiFunction dispatcher(FUNCTION_ADDR(EntryHookTrampoline));
   __ mov(ip, Operand(ExternalReference(
                  &dispatcher, ExternalReference::BUILTIN_CALL, isolate())));
 #endif
@@ skipping 1448 matching lines @@
   CallApiFunctionAndReturn(masm, api_function_address, thunk_ref,
                            kStackUnwindSpace, NULL, return_value_operand, NULL);
 }
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_S390