[analyzer] Add test directory for scan-build.

Authored by dcoughlin on Nov 4 2019, 8:26 PM.


[analyzer] Add test directory for scan-build.

The static analyzer's scan-build script is critical infrastructure but
is not well tested. To start to address this, add a new test directory under
tests/Analysis for scan-build lit tests and seed it with several tests. The
goal is that future scan-build changes will be accompanied by corresponding

Differential Revision: https://reviews.llvm.org/D69781