PECOFF: Do not use LayoutPass and instead use simpler one.

The LayoutPass is one of the slowest pass. This change is to skip
that pass. This change not only improve performance but also improve
maintainability of the code because the LayoutPass is pretty complex.

Previously we used the LayoutPass to sort all atoms in a specific way,
and reorder them again for PE/COFF in GroupedSectionPass.

I spent time on improving and fixing bugs in the LayoutPass (e.g.
r193029), but the pass is still hard to understand and hard to use.
It's better not to depend on that if we don't need. For PE/COFF, we
just wanted to sort atoms in the same order as the file order in the
command line.

The feature we used in the LayoutPass is now simplified to
compareByPosition function in OrderPass.cpp. The function is just 5
lines.

This patch changes the order of final output because it changes the
sort order a bit. The output is still correct, though.

llvm-svn: 227500