Auto merge of #49904 - michaelwoerister:no-debug-attr, r=alexcrichton

Work around LLVM debuginfo problem in librustc_driver.

Works around a problem (https://github.com/rust-lang/rust/issues/48910) with global variable debuginfo generation for `rustc_driver::get_trans::LOAD` by applying `#[no_debug]` to it (which just disables debuginfo generation for that variable). This way we can build the compiler with debuginfo again.

Since the problem is also present in beta, this workaround might have to be backported.

r? @alexcrichton