MFC r333401 (by emaste):

lld: Omit PT_NOTE for SHT_NOTE without SHF_ALLOC

A non-alloc note section should not have a PT_NOTE program header.

Found while linking ghc (Haskell compiler) with lld on FreeBSD. Haskell
emits a .debug-ghc-link-info note section (as the name suggests, it
contains link info) as a SHT_NOTE section without SHF_ALLOC set.

For this case ld.bfd does not emit a PT_NOTE segment for
.debug-ghc-link-info. lld previously emitted a PT_NOTE with p_vaddr = 0
and FreeBSD's rtld segfaulted when trying to parse a note at address 0.

LLVM PR: https://llvm.org/pr37361
LLVM review: https://reviews.llvm.org/D46623

PR: 226872
Reviewed by: dim
Sponsored by: The FreeBSD Foundation