Rollup merge of #72441 - doctorn:late-bound-lifetime-ice, r=nikomatsakis

Fix ICE with explicit late-bound lifetimes

Rather than returning an explicit late-bound lifetime as a generic argument count mismatch (which is not necessarily true), this PR propagates the presence of explicit late-bound lifetimes.

This avoids an ICE that can occur due to the presence of explicit late-bound lifetimes when building generic substitutions by explicitly ignoring them.

r? @varkor

cc @davidtwco (this removes a check you introduced in #60892)

Resolves #72278

Author: RalfJung