Use the sys::ExecuteAndWait that takes StringRefs.

Also don't depend on Program.h including PathV1.h.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@183935 91177308-0d34-0410-b5e6-96231b3b80d8
Followup to r183931 to fix the lambda conversion-to-block-pointer member.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@183942 91177308-0d34-0410-b5e6-96231b3b80d8