Modules and Tooling tests in particular tend to want to change the cwd,
so we were missing test coverage in this area on Windows. It should now
be easier to write such portable tests.
llvm-svn: 231029
* Put all input files under Inputs/, move corresponding tests into test/Modules.
* Rename a modulemap test file to [...].modulemap, and teach lit that such files are tests.
llvm-svn: 226875