Apply size optimizations to panic machinery and some cold functions * std dependencies gimli and addr2line are now built with opt-level=s * various panic-related methods and `#[cold]` methods are now marked `#[optimize(size)]` Panics should be cold enough that it doesn't make sense to optimize them for speed. The only tradeoff here is if someone does a lot of backtrace captures (without panics) and printing then the opt-level change might impact their perf. Seems to be the first use of the optimize attribute. Tracking issue #54882