Add AllocUnwrap trait, which provides alloc_unwrap and alloc_expect and is implemented for Option and Result
Refactor alloc_panic to use a function like the stdlib. This allows us to mark that function as #[cold] and #[inline(never)], hopefully reducing the inline size of the alloc_panic macro and also improving branch prediction.
AllocUnwraptrait, which providesalloc_unwrapandalloc_expectand is implemented forOptionandResultalloc_panicto use a function like the stdlib. This allows us to mark that function as#[cold]and#[inline(never)], hopefully reducing the inline size of thealloc_panicmacro and also improving branch prediction.