Update test case to include the original source code & account for some...

Update test case to include the original source code & account for some changes in clang's order of emission

I'd added some stuff to this test case without adding the original
source, which makes updating/adding further stuff rather difficult. So
update it first (& it seems in the interim Clang's changed its output
order a bit, so adjust the CHECK lines to account for that - rather than
hand hacking the IR order which just makes it harder to maintain/change
next time)

llvm-svn: 234911