Before this patch type traits are checked in Parser, so use type traits
directly did not cause assertion faults. However if type traits are initialized
from a template, we didn't perform arity checks before evaluating. This
patch moves arity checks from Parser to Sema, and performing arity
checks in Sema actions, so type traits get checked corretly.
Crash input:
```
template<class... Ts> bool b = __is_constructible(Ts...);
bool x = b<>;
```
After this patch:
```
clang/test/SemaCXX/type-trait-eval-crash-issue-57008.cpp:5:32: error: type trait requires 1 or more arguments; have 0 arguments
template<class... Ts> bool b = __is_constructible(Ts...);
^~~~~~~~~~~~~~~~~~
clang/test/SemaCXX/type-trait-eval-crash-issue-57008.cpp:6:10: note: in instantiation of variable template specialization 'b<>' requested here
bool x = b<>;
^
1 error generated.
```
See https://godbolt.org/z/q39W78hsK.
Fixes https://github.com/llvm/llvm-project/issues/57008
Reviewed By: aaron.ballman
Differential Revision: https://reviews.llvm.org/D131423
e5825190b8