Switch the code generator (except the JIT) onto the new DebugLoc

Switch the code generator (except the JIT) onto the new DebugLoc
representation.  This eliminates the 'DILocation' MDNodes for
file/line/col tuples from -O0 -g codegen.

This remove the old DebugLoc class, making it a typedef for DebugLoc,
I'll rename NewDebugLoc next.

I didn't update the JIT to use the new apis, so it will continue to
work, but be as slow as before.  Someone should eventually do this
or, better yet, rip out the JIT debug info stuff and build the JIT
on top of MC.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@100209 91177308-0d34-0410-b5e6-96231b3b80d8