[clang-tidy] Don't generate fix for argument constructed from std::initializer_list.

Summary:
A follow-up fix of rL311652.

The previous `vector` in our test is different with `std::vector`, so
The check still generates fixes for std::vector (`auto p =
std::unique_ptr<Foo>(new Foo({1,2,3}))`) in real world, the patch makes the
vector behavior in test align with std::vector (both AST nodes are the same now).

Reviewers: ilya-biryukov, alexfh

Reviewed By: ilya-biryukov

Subscribers: klimek, xazax.hun, cfe-commits

Differential Revision: https://reviews.llvm.org/D41852

llvm-svn: 322822