[AST] Dump argument types for TypeTraitExpr. (#89370)

The argument types are not modeled as children of TypeTraitExpr,
therefore they are not dumped with the default implementation.

Dumping them is really useful for ad-hoc debugging, context #89358

GitOrigin-RevId: 70abbd9084e25d2485edfeb252b603b3910a23bc
3 files changed