Make clang's static analyzer checks available through clang-tidy.

This is implemented in a way that the current static analyzer
architecture allows, in the future we might want to revisit this.

With this change static analyzer checks are available from clang-tidy
by specifying -checks=clang-analyzer-<name>.

This change also fixes the use of the compilation database to allow
clang-tidy to be used like any other clang tool.

git-svn-id: https://llvm.org/svn/llvm-project/clang-tools-extra/trunk@194707 91177308-0d34-0410-b5e6-96231b3b80d8