Remove host offloading copy checks from HloVerifier. Due to float propagation and float normalization being separate passes, host offloading copies can be multi-precision (at least temporarily). Float normalization will fix that and insert a convert.

Remove host offloading copy checks from HloVerifier. Due to float propagation and float normalization being separate passes, host offloading copies can be multi-precision (at least temporarily). Float normalization will fix that and insert a convert. #958