ELFObjectWriter: Don't sort non-local symbols

As we don't sort local symbols, don't sort non-local symbols.  This makes
non-local symbols appear in their register order, which matches GNU as. The
register order is nice in that you can write tests with interleaved CHECK
prefixes, e.g.

```
// CHECK: something about foo
.globl foo
foo:
// CHECK: something about bar
.globl bar
bar:
```

With the lexicographical order, the user needs to place lexicographical smallest
symbol first or keep CHECK prefixes in one place.

GitOrigin-RevId: 962b29d7162c8b470ea70540c48d11c2f35d7561
23 files changed