[analyzer] Look through SubstNonTypeTemplateParmExprs.

We were treating this like a CXXDefaultArgExpr, but
SubstNonTypeTemplateParmExpr actually appears when a template is
instantiated, i.e. we have all the information necessary to evaluate it.
This allows us to inline functions like llvm::array_lengthof.

<rdar://problem/11949235>

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@160846 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed