[ptr-compr] Add missing else on representation change

In https://chromium-review.googlesource.com/c/v8/v8/+/1621941 we added
missing representation changes. By changing the return to an assignation,
we forgot to include the (now needed) else.

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: Ibc54a24ea4430fd43d70251ef1a44ef15c06aa46
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1678659Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Commit-Queue: Santiago Aboy Solanes <solanes@chromium.org>
Cr-Commit-Position: refs/heads/master@{#62412}

src/compiler/representation-change.cc

@@ -462,10 +462,11 @@ Node* RepresentationChanger::GetTaggedPointerRepresentationFor(
              use_info.type_check() == TypeCheckKind::kHeapObject) {
     if (!output_type.Maybe(Type::SignedSmall())) {
       op = machine()->ChangeCompressedPointerToTaggedPointer();
+    } else {
+      // TODO(turbofan): Consider adding a Bailout operator that just deopts
+      // for CompressedSigned output representation.
+      op = simplified()->CheckedCompressedToTaggedPointer(use_info.feedback());
     }
-    // TODO(turbofan): Consider adding a Bailout operator that just deopts
-    // for CompressedSigned output representation.
-    op = simplified()->CheckedCompressedToTaggedPointer(use_info.feedback());
   } else {
     return TypeError(node, output_rep, output_type,
                      MachineRepresentation::kTaggedPointer);
@@ -654,10 +655,11 @@ Node* RepresentationChanger::GetCompressedPointerRepresentationFor(
              use_info.type_check() == TypeCheckKind::kHeapObject) {
     if (!output_type.Maybe(Type::SignedSmall())) {
       op = machine()->ChangeTaggedPointerToCompressedPointer();
+    } else {
+      // TODO(turbofan): Consider adding a Bailout operator that just deopts
+      // for TaggedSigned output representation.
+      op = simplified()->CheckedTaggedToCompressedPointer(use_info.feedback());
     }
-    // TODO(turbofan): Consider adding a Bailout operator that just deopts
-    // for TaggedSigned output representation.
-    op = simplified()->CheckedTaggedToCompressedPointer(use_info.feedback());
   } else if (output_rep == MachineRepresentation::kBit) {
     // TODO(v8:8977): specialize here and below
     node = GetTaggedPointerRepresentationFor(node, output_rep, output_type,