Remove the program class.

It was only used to implement ExecuteAndWait and ExecuteNoWait. Expose just
those two functions and make Execute and Wait implementations details.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@183864 91177308-0d34-0410-b5e6-96231b3b80d8
12 files changed