Rollup merge of #145005 - tardyp:lto_big_filesize, r=bjorn3

strip prefix of temporary file names when it exceeds filesystem name length limit

When doing lto, rustc generates filenames that are concatenating many information.

In the case of this testcase, it is concatenating crate name and rust file name, plus some hash, and the extension. In some other cases it will concatenate even more information reducing the maximum effective crate name to about 110 chars on linux filesystems where filename max length is 255

This commit is ensuring that the temporary file names are limited in size, while still reasonably ensuring the unicity (with hashing of the stripped part)

Fix: rust-lang/rust#49914

Author: Zalathar