[wasm-simd][x64] Optimize v128.not

Bug: v8:11471
Change-Id: Ie09f1f8e7b52b22e232bf382381c40037cf00986
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2708755Reviewed-by: Bill Budge <bbudge@chromium.org>
Commit-Queue: Zhi An Ng <zhin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#72932}

src/compiler/backend/x64/code-generator-x64.cc

@@ -3787,14 +3787,12 @@ CodeGenerator::CodeGenResult CodeGenerator::AssembleArchInstruction(
       XMMRegister dst = i.OutputSimd128Register();
       XMMRegister src = i.InputSimd128Register(0);
       if (dst == src) {
-        __ Movdqa(kScratchDoubleReg, dst);
-        __ Pcmpeqd(dst, dst);
+        __ Pcmpeqd(kScratchDoubleReg, kScratchDoubleReg);
         __ Pxor(dst, kScratchDoubleReg);
       } else {
         __ Pcmpeqd(dst, dst);
         __ Pxor(dst, src);
       }
-
       break;
     }
     case kX64S128Select: {