[analyzer] Mark the root SVal class as isPodLike.

Pure optimization, no functionality change. Probably does not make much
of a difference, but it's free.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@176229 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed