Much to my surprise, '-disable-llvm-optzns' which I thought was the
magical flag I wanted to get at the raw LLVM IR coming out of Clang
deosn't do that. It still runs some passes over the IR. I don't want
that, I really want the *raw* IR coming out of Clang and I strongly
suspect everyone else using it is in the same camp.

There is actually a flag that does what I want that I didn't know about
called '-disable-llvm-passes'. I suspect many others don't know about it
either. It both does what I want and is much simpler.

This removes the confusing version and makes that spelling of the flag
an alias for '-disable-llvm-passes'. I've also moved everything in Clang
to use the 'passes' spelling as it seems both more accurate (*all* LLVM
passes are disabled, not just optimizations) and much easier to remember
and spell correctly.

This is part of simplifying how Clang drives LLVM to make it cleaner to
wire up to the new pass manager.

Differential Revision: https://reviews.llvm.org/D28047

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@290392 91177308-0d34-0410-b5e6-96231b3b80d8