Fix impIntrinsic to not raise asserts for the AltJit scenario (#76048)

Fix impIntrinsic to not raise asserts for the AltJit scenario (#76048)

* Fix impIntrinsic to not raise asserts for the AltJit scenario

* Respond to PR feedback

* Specially handle NI_Vector64/128/256_* intrinsics where not all overloads are valid

* Change the AltJit intrinsic handling so we get no asserts

* Apply suggestions from code review

Co-authored-by: Jan Kotas <jkotas@microsoft.com>
* Apply suggestions from code review

* Fixing a build error

* Applying formatting patch

Co-authored-by: Jan Kotas <jkotas@microsoft.com>