PPC/s390: [liftoff] Change FillStackSlotsWithZero to use bytes

Port 785fa6b4

R=zhin@chromium.org, joransiu@ca.ibm.com, jyan@ca.ibm.com, michael_dawson@ca.ibm.com
BUG=
LOG=N

Change-Id: I34f98cef7b78c694ba909e02d8c7bb251c7b5301
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1949153Reviewed-by: Junliang Yan <jyan@ca.ibm.com>
Commit-Queue: Milad Farazmand <miladfar@ca.ibm.com>
Cr-Commit-Position: refs/heads/master@{#65336}

src/wasm/baseline/s390/liftoff-assembler-s390.h

@@ -171,7 +171,7 @@ void LiftoffAssembler::FillStackSlotsWithZero(uint32_t start, uint32_t size) {
     // Use r3 for start address (inclusive), r4 for end address (exclusive).
     push(r3);
     push(r4);
-    SubP(r3, fp, Operand(liftoff::GetStackSlotOffset(start + remainder)));
+    SubP(r3, fp, Operand(liftoff::GetStackSlotOffset(start + size)));
     SubP(r4, fp, Operand(liftoff::GetStackSlotOffset(start)));
 
     Label loop;