[ptr-compr][turbofan] Use Mach Rep information to choose the decompression

Decompressing with Any just chooses one of the decompressions (Signed or
Pointer). Since we already know which decompression it is going to choose,
we save ourselves a whole bunch of instructions by just skipping that.

Cq-Include-Trybots: luci.v8.try:v8_linux64_pointer_compression_rel_ng
Cq-Include-Trybots: luci.v8.try:v8_linux64_arm64_pointer_compression_rel_ng
Bug: v8:7703
Change-Id: I0173931536e7ba83fa3572ceb50b176409f0b6c5
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1691916Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
Commit-Queue: Santiago Aboy Solanes <solanes@chromium.org>
Cr-Commit-Position: refs/heads/master@{#62602}

src/compiler/representation-change.cc

@@ -593,7 +593,11 @@ Node* RepresentationChanger::GetTaggedRepresentationFor(
       return TypeError(node, output_rep, output_type,
                        MachineRepresentation::kTagged);
     }
-  } else if (IsAnyCompressed(output_rep)) {
+  } else if (output_rep == MachineRepresentation::kCompressedSigned) {
+    op = machine()->ChangeCompressedSignedToTaggedSigned();
+  } else if (output_rep == MachineRepresentation::kCompressedPointer) {
+    op = machine()->ChangeCompressedPointerToTaggedPointer();
+  } else if (output_rep == MachineRepresentation::kCompressed) {
     op = machine()->ChangeCompressedToTagged();
   } else {
     return TypeError(node, output_rep, output_type,