[ELF] Support --no-align-segments.

lld generates an ELF by adhering to the ELF spec by aligning vma/fileoffset to a
page boundary, but this becomes an issue when dealing with large pages. This
adds support so that lld generated executables adheres to the ELF spec with the
rule vma % p_align = offset % p_align.

This is supported by the flag --no-align-segments.

This could be the default in few targets like X86_64 to save space on disk.

llvm-svn: 221571