[maglev] Use liveness to filter unused register in GeneratorStore

Otherwise we could point to a potentially dead (not allocable)
input to GeneratorStore.

Bug: v8:7700
Change-Id: I113a02e0c1a3eb1b817dc4eb8f538cf40a1d0d3f
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3867729
Auto-Submit: Victor Gomes <victorgomes@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Victor Gomes <victorgomes@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82904}

src/maglev/maglev-graph-builder.cc

@@ -2809,8 +2809,12 @@ void MaglevGraphBuilder::VisitSuspendGenerator() {
   for (int i = 1 /* skip receiver */; i < parameter_count(); ++i) {
     node->set_parameters_and_registers(arg_index++, GetArgument(i));
   }
+  const compiler::BytecodeLivenessState* liveness = GetOutLiveness();
   for (int i = 0; i < args.register_count(); ++i) {
-    node->set_parameters_and_registers(arg_index++, GetTaggedValue(args[i]));
+    ValueNode* value = liveness->RegisterIsLive(args[i].index())
+                           ? GetTaggedValue(args[i])
+                           : GetRootConstant(RootIndex::kOptimizedOut);
+    node->set_parameters_and_registers(arg_index++, value);
   }
   AddNode(node);