Fix linkage bug that miscompiled variable templates instantiated from similarly named local types. In essence, this bug ensures that the x<Foo> specialization in function foo() defined as follows differs between two distinct translation units.
    static int &foo() {
       struct Foo { };
       return x<Foo>;
    }

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@212233 91177308-0d34-0410-b5e6-96231b3b80d8