[PATCH] Reland [Clang] Un-break scan-build after integrated-cc1 change

The issue was reported by @xazax.hun here: https://reviews.llvm.org/D69825#1827826

"This patch (D69825) breaks scan-build-py which parses the output of "-###" to get -cc1 command. There might be other tools with the same problems. Could we either remove (in-process) from CC1Command::Print or add a line break?

Having the last line as a valid invocation is valuable and there might be tools relying on that."

Differential Revision: https://reviews.llvm.org/D72982