Rollup merge of #141035 - lqd:lld-warn, r=Mark-Simulacrum

turn lld warning on old gccs into info log

As discussed in #140964 and IRL, this PR switches the spammy warning shown unconditionally when an old gcc doesn't support `-fuse-ld=lld` and we retry linking without it, to an info debug log so we don't lose it.

r? `@Mark-Simulacrum`

Fixes #140964

Author: matthiaskrgr