Improving the SIMD codegen for SIMD12 load/store (#80083)

Improving the SIMD codegen for SIMD12 load/store (#80083)

* Improving the SIMD codegen for SIMD12 load/store

* Apply formatting patch

* Ensure the right index is used for insertps

* Ensure emitIns_SIMD_* is used for insertps to handle the non-rmw form

* Fix the input size flag for extractps

* Fix an issue where the second half of a TYP_SIMD12 store used the wrong register

* Ensure relocatable handles for TYP_SIMD12 load/stores are not contained

* Ensure arm32 can build