Teach Scopes whether they will end up being lazily compiled or not

src/ast/ast.h

Index: src/ast/ast.h
diff --git a/src/ast/ast.h b/src/ast/ast.h
index a6661becf25a7cdf2d1a95dfacf31a48e66a7034..6cb252fae9392a869143de302c7aad217e724385 100644
--- a/src/ast/ast.h
+++ b/src/ast/ast.h
@@ -2652,9 +2652,7 @@ class FunctionLiteral final : public Expression {
   bool should_eager_compile() const {
     return ShouldEagerCompile::decode(bit_field_);
   }
-  void set_should_eager_compile() {
-    bit_field_ = ShouldEagerCompile::update(bit_field_, true);
-  }
+  void set_should_eager_compile();
 
   // A hint that we expect this function to be called (exactly) once,
   // i.e. we suspect it's an initialization function.