[wasm-simd][liftoff] Add is_fp_pair case

Add a case for is_fp_pair in StackTransferRecipe, when moving registers.
This is similar to the is_gp_pair case, but we only need to check the
low fp register, and move both low and high if the low fp register is
different.

Bug: v8:9909
Change-Id: I02f72f6390a1b2802afce5e91ed227b749d838ae
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2013223
Commit-Queue: Zhi An Ng <zhin@chromium.org>
Reviewed-by: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#65923}

src/wasm/baseline/liftoff-assembler.cc

@@ -159,6 +159,14 @@ class StackTransferRecipe {
         MoveRegister(dst.high(), src.high(), kWasmI32);
       return;
     }
+    if (src.is_fp_pair()) {
+      DCHECK_EQ(kWasmS128, type);
+      if (dst.low() != src.low()) {
+        MoveRegister(dst.low(), src.low(), kWasmF64);
+        MoveRegister(dst.high(), src.high(), kWasmF64);
+      }
+      return;
+    }
     if (move_dst_regs_.has(dst)) {
       DCHECK_EQ(register_move(dst)->src, src);
       // Non-fp registers can only occur with the exact same type.