[llvm] [ADT] Skip destroying trivially destructible values in DenseMap (PR #106934)

[Jakub Kuderski via llvm-commits]

kuhar wrote:

> > Test?
> 
> Not sure this is testable? If they're trivially destructible, it wouldn't be possible to observe the difference between destroying them and not destroying them, right?

We could have the test for the non-trivially destructible case to make sure we don't unintentionally skip destructors.

https://github.com/llvm/llvm-project/pull/106934