Remove exceptions from the Path::create*OnDisk methods. Update their users
to handle error messages via arguments and result codes.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@29840 91177308-0d34-0410-b5e6-96231b3b80d8
Make sys::Program::ExecuteAndWait not throw exceptions and update any
affected code. It now return -9999 to signal that the program couldn't be
executed. Only one case (in bugpoint) actually examines the result code.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@29785 91177308-0d34-0410-b5e6-96231b3b80d8
