[Driver] Suggest correctly spelled driver options

Summary:
Depends on https://reviews.llvm.org/D41732.

Utilities such as `opt`, when invoked with arguments that are very
nearly spelled correctly, suggest the correctly spelled options:

```
bin/opt -hel
opt: Unknown command line argument '-hel'.  Try: 'bin/opt -help'
opt: Did you mean '-help'?
```

Clang, on the other hand, prior to this commit, does not:

```
bin/clang -hel
clang-6.0: error: unknown argument: '-hel'
```

This commit makes use of the new libLLVMOption API from
https://reviews.llvm.org/D41732 in order to provide correct suggestions:

```
bin/clang -hel
clang-6.0: error: unknown argument: '-hel', did you mean '-help'?
```

Test Plan: `check-clang`

Reviewers: yamaguchi, v.g.vassilev, teemperor, ruiu, bruno

Reviewed By: bruno

Subscribers: bruno, jroelofs, cfe-commits

Differential Revision: https://reviews.llvm.org/D41733

llvm-svn: 321917