Finish refactoring the tool selection logic.

The general pattern now is that Foobar::constructTool only creates tools
defined in the tools::foobar namespace and then delegates to the parent.

The remaining duplicated code is now in the tools themselves.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@177368 91177308-0d34-0410-b5e6-96231b3b80d8
5 files changed