[NPM][LTO] Update buildLTODefaultPipeline to be more in-line with the old pass manager

The NPM LTO pipeline has a lot of fixme's and missing passes, causing a
lot of regressions after the switch in c70737ba. Notably unrolling and
vectorization were both disabled, but many other passes are missing
compared to the old pass manager. This attempt to enable the most
obvious missing passes like the unroller, vectorization and other loop
passes, fixing the existing FIXME comments.

Differential Revision: https://reviews.llvm.org/D96780