Fix Driver tests to check return value of parse(), simplify subclassing, and remove unneeded instance variables

llvm-svn: 186440

llvm-svn: 186428

llvm-svn: 186427

llvm-svn: 184050

llvm-svn: 183806

llvm-svn: 183724

llvm-svn: 183622

llvm-svn: 183604

llvm-svn: 183034

llvm-svn: 182988

llvm-svn: 182985

llvm-svn: 182980

llvm-svn: 182971

llvm-svn: 182970

Uses ConcRT and PPL on Windows.

llvm-svn: 179397

llvm-svn: 178798

llvm-svn: 172993

This is based on code by Jeffrey Yasskin. It has been modified to compile
with MSVC and reformated to LLVM style.

llvm-svn: 172512

llvm-svn: 170483