Fix type printing of array template args

The code example:
```
constexpr const char kEta[] = "Eta";
template <const char*, typename T> class Column {};
using quick = Column<kEta,double>;

void lookup() {
  quick c1;
  c1.ls();
}
```

emits error: no member named 'ls' in 'Column<&kEta, double>'. The patch fixes
the printed type name by not printing the ampersand for array types.

Differential Revision: https://reviews.llvm.org/D36368