[liftoff] Clean up unused method and parameter names

This helper method is no longer needed since we have removed all usages
of indexes for the purpose of accessing stack spill slot.

The parameter names for FillStackSlotsWithZero in the header file is
also corrected to match the names in the implementation.

Bug: v8:9909
Change-Id: I6093f020e05701ff8e8d6362015d2e07165b2397
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1950224Reviewed-by: Clemens Backes <clemensb@chromium.org>
Commit-Queue: Zhi An Ng <zhin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#65326}

src/wasm/baseline/liftoff-assembler.h

@@ -43,15 +43,6 @@ class LiftoffAssembler : public TurboAssembler {
     return kStackSlotSize;
   }
 
-  // TODO(zhin): Temporary for migration from index to offset.
-  inline static uint32_t GetStackOffsetFromIndex(uint32_t index) {
-    // The idea of a stack offset changed from being relative to first stack
-    // offset (instance offset + kStackSlotSize), to being relative to instance
-    // offset. So the stack offset of a particular index needs to take into
-    // account the size of the first slot.
-    return (index + 1) * LiftoffAssembler::kStackSlotSize;
-  }
-
   class VarState {
    public:
     enum Location : uint8_t { kStack, kRegister, kIntConst };
@@ -441,7 +432,7 @@ class LiftoffAssembler : public TurboAssembler {
   // Only used on 32-bit systems: Fill a register from a "half stack slot", i.e.
   // 4 bytes on the stack holding half of a 64-bit value.
   inline void FillI64Half(Register, uint32_t offset, RegPairHalf);
-  inline void FillStackSlotsWithZero(uint32_t index, uint32_t count);
+  inline void FillStackSlotsWithZero(uint32_t start, uint32_t size);
 
   // i32 binops.
   inline void emit_i32_add(Register dst, Register lhs, Register rhs);