Fix a couple issues with Vector128.Get/WithElement (#52985)

Fix a couple issues with Vector128.Get/WithElement (#52985)

* Fix an issue with Vector128.WithElement around unused nodes for pre SSE4.1

* Fixing the expected exception for a structreturn test

* Ensure we check if the baseline SIMD ISAs are supported in morph

* Ensure TYP_SIMD12 LclVar can be cloned in lowering

* Fixing up the non SSE41 path for WithElement

* Applying formatting patch

* Ensure ReplaceWithLclVar lowers the created LclVar and assignment

* Don't check the JitLog for compiled methods when the baseline ISAs aren't supported

* Address PR feedback

* Responding to more PR feedback

* Applying formatting patch

* Fixing the more PR review feedback