Rollup merge of #147925 - fneddy:fix_big_endian_GVN_tests, r=saethlin

Fix tests for big-endian

The tests fail on s390x and presumably other big-endian systems, due to check of raw alloc values in the MIR output.

To fix the tests remove the raw bytes from the MIR output (via: compile-flags: -Zdump-mir-exclude-alloc-bytes) and update the matching diffs.

Author: Zalathar