Bring r240130 back.

Bring r240130 back.

Now that pr23900 is fixed, we can bring it back with no changes.

Original message:

Make all temporary symbols unnamed.

What this does is make all symbols that would otherwise start with a .L
(or L on MachO) unnamed.

Some of these symbols still show up in the symbol table, but we can just
make them unnamed.

In order to make sure we produce identical results when going thought assembly,
all .L (not just the compiler produced ones), are now unnamed.

Running llc on llvm-as.opt.bc, the peak memory usage goes from 208.24MB to
205.57MB.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@240302 91177308-0d34-0410-b5e6-96231b3b80d8