[MSan] Update type for MsanMetadataPtrForLoadN and MsanMetadataPtrForStoreN (#135040)
Changed last parameter type for `MsanMetadataPtrForLoadN` and
`MsanMetadataPtrForStoreN` from `i64` to `IntptrTy` to keep it
consistent with call in `getShadowOriginPtrKernelNoVec`
Co-authored-by: Kamil Kashapov <kashapov@ispras.ru>