LibJS/JIT: Support the GetVariable bytecode instruction

Author: https://github.com/awesomekling
Commit: dabaaabfc0
Pull-request: https://github.com/SerenityOS/serenity/pull/21619
Reviewed-by: https://github.com/Hendiadyoin1

Userland/Libraries/LibJS/JIT/Compiler.h

@@ -95,6 +95,7 @@ private:
     void compile_get_by_id(Bytecode::Op::GetById const&);
     void compile_get_by_value(Bytecode::Op::GetByValue const&);
     void compile_get_global(Bytecode::Op::GetGlobal const&);
+    void compile_get_variable(Bytecode::Op::GetVariable const&);
 
     void compile_put_by_id(Bytecode::Op::PutById const&);
     void compile_put_by_value(Bytecode::Op::PutByValue const&);