Rollup merge of #119828 - azhogin:azhogin/collapse_debuginfo_improved…

…_attr, r=petrochenkov

Improved collapse_debuginfo attribute, added command-line flag

Improved attribute collapse_debuginfo with variants: `#[collapse_debuginfo=(no|external|yes)]`.
Added command-line flag for default behaviour.
Work-in-progress: will add more tests.

cc rust-lang/rust#100758