LibJS/Bytecode: Unwind to closest unwind boundary on Throw

This will leave any lexical/variable environments on the way to the
closest unwind context boundary.

This will not leave the closest unwind context, as we still need the
unwind context to perform the Throw instruction correctly.

Userland/Libraries/LibJS/Bytecode/ASTCodegen.cpp

@@ -1441,6 +1441,7 @@ Bytecode::CodeGenerationErrorOr<void> UpdateExpression::generate_bytecode(Byteco
 Bytecode::CodeGenerationErrorOr<void> ThrowStatement::generate_bytecode(Bytecode::Generator& generator) const
 {
     TRY(m_argument->generate_bytecode(generator));
+    generator.perform_needed_unwinds<Bytecode::Op::Throw>();
     generator.emit<Bytecode::Op::Throw>();
     return {};
 }