devel/llvm1[4567]: keep backport patches local

The patches generated by adding .patch to a github commit URL are
unstable and the output of some of them changed recently. It's
concivable this will be fixed, but they probably won't make any
long term guarantees so store the patches in the ports tree instead of
downloading them.

PR: 292291
MFH: 2026Q1
Sponsored by: DARPA, AFRL
See also: https://github.com/orgs/community/discussions/184094

(cherry picked from commit d5c827648ead25c364859541c957a09ba0c276fb)