lintian accounted for more than half the wall clock of a Jenkinsfile.sourcepackage run: for a source package it unpacks the whole openmodelica orig tarball again and scans every file, once per built revision. Nothing consumes its output - it is neither archived nor gated on - so drop it with debuild --no-lintian. That also removes a failure mode where a new lintian version invents an error tag and fails the nightly.
Compress the orig tarball with `xz -T0` instead of tar's single threaded `cJf`. Same preset, so the tarball only grows a fraction of a percent from the block splitting, and it decompresses in parallel too. Note this wants roughly 100 MB of encoder memory per core; pin the thread count if that ever gets tight on the builder.
