[codegen][arm64] Use ldp instead of 2 ldrs before a TailCall

A port of https://chromium-review.googlesource.com/c/v8/v8/+/2011103
for arm64. Saves 2784 bytes (0.2%) in the arm64.release embedded.S

Change-Id: Ifae6b3f220356ab286b49750c7ae422e4b6d4306
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2013107Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Commit-Queue: Joey Gouly <joey.gouly@arm.com>
Cr-Commit-Position: refs/heads/master@{#65911}

src/compiler/backend/arm64/code-generator-arm64.cc

@@ -503,8 +503,11 @@ void CodeGenerator::AssembleDeconstructFrame() {
 
 void CodeGenerator::AssemblePrepareTailCall() {
   if (frame_access_state()->has_frame()) {
-    __ Ldr(lr, MemOperand(fp, StandardFrameConstants::kCallerPCOffset));
-    __ Ldr(fp, MemOperand(fp, StandardFrameConstants::kCallerFPOffset));
+    static_assert(
+        StandardFrameConstants::kCallerFPOffset + kSystemPointerSize ==
+            StandardFrameConstants::kCallerPCOffset,
+        "Offsets must be consecutive for ldp!");
+    __ Ldp(fp, lr, MemOperand(fp, StandardFrameConstants::kCallerFPOffset));
   }
   frame_access_state()->SetFrameAccessToSP();
 }