[maglev] Keep BytecodeArray alive via deopt literals

Do the same trick as TurboFan, keeping the BytecodeArray alive by
holding it strongly in the deopt literals.

Bug: v8:7700
Change-Id: I8f8472674b08df3ca18aff58172e7ba83d09a620
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3647358
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Cr-Commit-Position: refs/heads/main@{#80519}

src/maglev/maglev-code-generator.cc

@@ -347,6 +347,13 @@ class MaglevCodeGeneratorImpl final {
     processor_.ProcessGraph(graph_);
     EmitDeferredCode();
     EmitDeopts();
+
+    // Add the bytecode to the deopt literals to make sure it's held strongly.
+    // TODO(leszeks): Do this fo inlined functions too.
+    GetDeoptLiteral(*code_gen_state_.compilation_info()
+                         ->toplevel_compilation_unit()
+                         ->bytecode()
+                         .object());
   }
 
   void EmitDeferredCode() {